Taxonomy of the Polygonum douglasii (Polygonaceae ... - WLU

Taxonomy of the Polygonum douglasii 

(Polygonaceae) complex with a new species from 

Oregon 

MIHAI COSTEA 1 AND FRANÇOIS J. TARDIF 

Costea, M. (University of Guelph, Department of Plant Agriculture, Guelph, 

ON, N1G 2W1, Canada; email: coste�amihai@hotmail.com) and F. J. Tardif (University 

of Guelph, Department of Plant Agriculture, Guelph, ON, N1G 2W1, 

Canada; e-mail: ftardif@uoguelph.ca). Taxonomy of the Polygonum douglasii 

(Polygonaceae) complex with a new species from Oregon. Brittonia 57: 1–27. 

2005.—The taxonomy of the Polygonum douglasii complex is revised. A summary 

of relevant taxonomic information is provided, along with a key to the 

species and subspecies, plus typification, synonymy, discussion, distribution, and 

ecology. Morphology and micromorphology of stems, leaves, perianth, pollen, 

and achenes are analyzed and illustrated. Based on these data, 12 species and two 

subspecies are recognized. A new species, P. gabrielae, is described and illustrated 

from Oregon. 

Key words: Polygonum douglasii complex, Polygonaceae, taxonomy, morphology, 

micromorphology. 

Polygonum L. s.str. is a cosmopolitan 

genus comprised of about 70 species divided 

into three sections (Haraldson, 

1978). The current study examines the taxonomy 

of a group of closely related species 

in section Duravia S. Watson, native 

to North America. One species in this 

group, P. douglasii Greene, has been interpreted 

(e.g., Hickman, 1993; Kartesz, 

1998) as a complex species comprising 

seven partially sympatric subspecies: 

subsp. douglasii, subsp. johnstonii (Munz.) 

J. C. Hickman, subsp. spergulariiforme 

(Meisn. ex Small) J. C. Hickman, subsp. 

majus (Meisn.) J. C. Hickman, subsp. nuttallii 

(Small) J. C. Hickman, subsp. austiniae 

(Greene) Murray, and subsp. engelmannii 

(Greene) Kartesz & Gandhi. Several 

other species, however, share the same 

close taxonomic affinities and geographic 

distribution with P. douglasii: P. tenue 

Michx., P. minimum S. Watson, P. cascadense 

W. H. Baker, and P. utahense Brenckle 

& Cottam. Should all these species 

1 Corresponding author 

be combined in a broadly defined P. douglasii? 

Furthermore, during the preparation 

of Polygonum s. str. for Flora of North 

America, collections within this range of 

variation were found that match none of 

these taxa. Therefore, the main purpose of 

this study is to analyze the variation patterns 

and relationships between these 

closely related taxa. Micromorphology of 

perianth lobes and leaves, as well as the 

morphology of pollen, have proved to be 

useful for the infrageneric classification of 

the tribe Polygoneae (Hedberg, 1946; 

Ronse Decraene & Akeroyd, 1988; Hong 

et al., 1998; Hong & Oh, 1999). Additionally, 

the surface of achenes was important 

to distinguish between species of the section 

Polygonum (Wolf & McNeill, 1986). 

Another aim of this study is to test the taxonomic 

usefulness of such micromorphological 

characters for this group of taxa. 

Methods 

MORPHOLOGY 

Descriptions and distribution of taxa are 

based on specimens from A, ALTA, CAS, 

Brittonia, 57(1), 2005, pp. 1–27. ISSUED: 31 March 2005 

� 2005, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A.

2 BRITTONIA 

[VOL. 57 

DAO, DC, DS, GH, F, JEPS, LL, MT, 

MTMG, NY, OAC, POM, QFA, RSA, 

SASK, TEX, UBC, UC, US, and USAS. 

Mature plants with leaves, flowers, and 

achenes are necessary for accurate determinations. 

Plants parasitized by homopteran 

insects are atypical. Their internodes are 

shortened, cymes have numerous flowers, 

and inflorescences are denser; flowers are 

brownish, sterile, and pedicels may be erect 

even in taxa in which they are normally reflexed. 

Papillae are easily observed on 

young stems or toward apices of mature 

stems and branches, at magnifications higher 

than 50�. Measurements of leaves and 

ocreae were made at the middle of the main 

stem. The state characters, ‘‘flowers 

closed,’’ ‘‘flowers semiopen,’’ and ‘‘flowers 

wide-open’’ were noted on herbarium specimens. 

Description of perianth refers to the 

fruiting perianth, which was measured from 

the joint with the pedicel. Morphology of 

pedicels was noted in fruit. Measurements 

of dry anthers were obtained from SEM 

pictures (see below). 

MICROMORPHOLOGY 

Samples (Appendix 1) were collected 

from typical herbarium specimens within 

the holdings of CAS, DS, GH, JEPS, NY, 

RSA, UC, and USAS. Samples were coated 

with 30 nm gold using an Emitech 

K550� Sputter Coater and examined with 

a Hitachi S-570 at 15 KV. Micromorphology 

of the following organs or plant parts 

was examined: mature stems and leaves, 

fruiting perianth, and pollen. Surface pattern 

of perianth was studied on the borders 

of the outer perianth lobes. Standard terminology 

for cell types and surface sculpturing 

patterns follows Ronse Decraene 

and Akeroyd (1988), Barthlott et al. 

(1998), and Hong et al. (1998). Pollen terminology 

follows Hoen (1999). Description 

of achene morphology and micromorphology 

follows the terminology developed 

by Wolf and McNeill (1986) and 

Ronse Decraene et al. (2000). 

STEMS 

Results 

Stems are 4-angled, with smooth (Fig. 

1A) or minutely and irregularly ribbed fac- 

es (Fig. 1C, D, F). Epidermis cells are rectangular 

or elongated, with epicuticular wax 

consisting of longitudinal rodlets (Fig. 1C). 

Stomata are frequent, mostly anisocytic 

(rarely a few may be anomocytic). Presence 

of papillae is a distinctive feature observed 

in many taxa. Papillae may be distributed 

on the stem angles or on the ribs and between 

these (Fig. 1C, D, F). They may be 

patent or more or less retrorse. Papillae 

shape varies from � spherical, 7–18 �m, 

located at the same level with the epidermis 

cells (Fig. 1A), conical with a swollen base, 

40–60 �m (Fig. 1B), to conical-elongated 

or cylindrical, 100–200 �m long, approaching 

hairs (Fig. 1C, D). Epicuticular wax of 

papillae is organized as parallel rodlets 

(Fig. 1B). 

LEAVES AND OCREAE 

Leaves are obviously jointed to ocreae, 

which may be short, funnelform 2–5 mm, 

or longer, 5–12 mm, with the free part becoming 

lacerate or disintegrating into a few 

fibers. Petioles are very short or absent. 

Blades are variably shaped, linear to round, 

and 1-veined. Leaf blade epidermis cells are 

irregularly shaped or elongated, with more 

or less undulate anticlinal walls. Stomata 

are usually present on both epidermis, and 

they are mostly anisocytic (rarely a few 

may be anomocytic). Margins of the leaves 

are often revolute (Fig. 2A), or sometimes 

plane. In P. utahense, the revolute margins 

join together on the abaxial side of the 

blade (Fig. 2B). Conical or conical-elongate 

papillae, similar to those present on the 

stems, may occur on the ocreae and lamina 

margins in many taxa (Fig. 1F, 2C, D). 

Presence of papillae on the rest of lamina 

has been documented only in P. utahense 

(Fig. 2B, F) and sometimes in P. spergulariiforme 

(Fig. 2E). Epicuticular wax is organized 

as longitudinal rodlets or threads 

(Fig. 2E); only in P. utahense do the rodlets 

form a reticulate pattern (Fig. 2F). 

PERIANTH 

The perianth consists of two outer tepals, 

one intermediate (transitional), and two inner 

tepals fused for 8–40% of their length. 

The outer and the intermediate perianth

2005] COSTEA & TARDIF: POLYGONUM DOUGLASII COMPLEX 

3 

FIG. 1. Micromorphology of stems. A. Polygonum tenue, arrows indicate papillae (scale bar � 100 �m). B. 

P. minimum (scale bar � 75 �m). C. P. spergulariiforme (scale bar � 100 �m). D. P. sawatchense subsp. 

oblivium (scale bar � 25 �m). E. P. sawatchense subsp. sawatchense (scale bar 50 � mm). F. P. nuttallii (scale 

bar � 50 mm).

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[VOL. 57 

FIG. 2. Micromorphology of leaves. A–D. Margin of the leaf. A. Polygonum sawatchense subsp. sawatchense 

(scale bar � 0.3 mm). B. P. utahense (scale bar � 0.3 mm). C. P. sawatchense subsp. oblivium (scale bar 

� 100 �m). D. P. spergulariiforme (scale bar � 100 �m). E, F. papillae on the leaf blade: E. P. spergulariiforme. 

F. P. utahense (scale bars � 30 �m).


5 

lobes are oblong-elliptic to oblong-obovate, 

often cucullate and overlapping, naviculate 

along their entire length or only in the upper 

1/4 (Fig. 3). Vasculature of tepals consists 

of a single vein, which may be 

branched or not. 

EPICUTICULAR WAX PATTERN OF PERIANTH 

LOBES 

Epidermis cells are irregularly shaped, 

elongated or rectangular (Figs. 4, 5). Stomata 

are usually present. The anticlinal 

walls are usually sinuate or sometimes 

straight or weakly undulate (Figs. 4, 5). 

Epicuticular wax sculpture pattern is variable 

and complex: 

Type 1. Epidermis cells with the periclinal 

walls more or less flat. Sculpture pattern 

is homogenous on the same cell. Wax 

rodlets may be arranged in a dense reticulate, 

intertwined pattern (Figs. 4C, 5E, 

F) or they may be more or less transversally 

oriented (Fig. 4A, B). 

Type 2. Epidermis cells with the periclinal 

walls evidently convex. Sculpture pattern 

is heterogeneous on the same cell: wax 

rodlets are � parallel among themselves 

and perpendicular to the long axis of 

cells on the lateral inclined faces and arranged 

in a dense reticulate and intertwined 

pattern on the more or less flat top 

of the periclinal walls (Fig. 4D–F, 5A– 

D). 

STAMENS 

Stamens are most commonly eight, arranged 

in two ‘‘whorls.’’ The outer whorl 

consists of five stamens and the inner of 

three stamens. Stamens in the outer 

‘‘whorl’’ may be reduced, sometimes entirely 

(e.g., P. sawatchense subsp. sawatchense). 

The base of the inner stamens is 

thickened and associated with a nectarial 

tissue. Anthers are short, 100–550 �m, pink 

to purple, rarely whitish. 

POLLEN 

The pollen belongs to the ‘‘Duravia 

type’’ described by Hedberg (1946). It is 

prolate, usually tricolporate with the exine 

semitectate-reticulate or microreticulate at 

the mesocolpia and poles, and microreticulate-foveolate 

or sometimes foveolate 

with microspinules around ectoapertures 

(Fig. 6). Two distinct types can be recognized 

based the size of the pollen grains, 

the reticulum sculpturing at the middle part 

of the mesocolpium and the sculpturing of 

ectoapertures: 

Type A. Pollen grains 20–26 �m long; mesocolpium 

is microreticulate with 1–7 

rows of lumina, 0.5–1(–1.1) �m indiameter, 

clearly differentiated or undifferentiated 

from the ectoapertures, which 

are microreticulate to tectate perforate, 

foveolate-punctate, sometimes with microspinules. 

● Subtype A1.—Mesocolpium is microreticulate 

and not clearly differentiated 

from the ectoapertures. Mesocolpium microreticulum 

with 4–7 rows of lumina, 

0.5–0.9 �m in diameter (Fig. 6A–C). 

● Subtype A2.—Mesocolpium is reticulate, 

clearly differentiated from ectoapertures. 

Mesocolpium reticulum with 1– 

5 rows of lumina, 0.9–1.1 �m in diameter 

(Fig. 6D, E). 

Type B. Pollen grains 28–33 �m; mesocolpium 

is reticulate with 1–2 rows of lumina, 

1.5–4 �m in diameter; mesocolpium 

is sharply differentiated from the 

ectoapertures, which are tectate imperforate, 

rarely punctate, with a few puncta 

(Fig. 6F–H). 

ACHENES 

Achenes are black, trigonous, ovate, 

ovate-lanceolate, elliptic, and enclosed in 

the perianth or exserted at maturity (Fig. 7). 

Faces are concave and subequal; one face 

is slightly broader than the other two (Fig. 

7). The exocarp is usually lustrous and 

smooth, or sometimes it may be striate-tubercled, 

especially near the edges and apex 

of achenes (Fig. 7C, F). Tubercles may be 

arranged in longitudinal rows, more or less 

following the anticlinal walls (Fig. 7D). 

Taxonomy 

Hickman (1984) included within P. 

douglasii five other species that share a significant 

area of sympatry: P. sawatchense

6 BRITTONIA 

[VOL. 57 

FIG. 3. Morphology of flowers. A. Polygonum douglasii. B. P. sawatchense subsp. oblivium. C. P. nuttallii. 

D. and E. P. gabrielae. F. P. sawatchense subsp. sawatchense. G. P. utahense. H. P. cascadense. I. P. engelmannii. 

J. P. austiniae. Scale bars � 1 mm.


7 

FIG. 4. Epicuticular wax sculpture pattern of perianth lobes. A. Polygonum tenue. B. P. douglasii. C. P. 

sawatchense subsp. sawatchense. D. P. sawatchense subsp. oblivium. E. P. spergulariiforme. F. P. majus. Scale 

bars � 20 �m.

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[VOL. 57 

FIG. 5. Epicuticular wax sculpture pattern of perianth lobes. A. Polygonum austiniae. B. P. utahense. C. P. 

engelmannii. D. P. gabrielae. E. P. minimum. F. P. nuttallii. Scale bars � 20 �m.


9 

FIG. 6. Morphology of pollen. A. P. douglasii. B. P. tenue. C. P. sawatchense subsp. sawatchense. D. P. 

sawatchense subsp. oblivium. E. P. minimum (scale bars � 5 �m). F. P. nuttallii (scale bar � 4 �m). G. P. 

gabrielae. H. P. majus (scale bar � 4 �m).

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[VOL. 57 

FIG. 7. Morphology and micromorphology of achenes. A. Polygonum sawatchense subsp. sawatchense. B. 

P. sawatchense subsp. oblivium. C. P. tenue. D. P. douglasii. E. P. majus. F. P. spergulariiforme. G. P. austiniae. 

H. P. engelmannii. I. P. gabrielae. J. P. utahense. Scale bar � 1 mm for all figures except Figure 7D where 

scale bar is 100 �m.


11 

Small, P. spergulariiforme Meisn. ex 

Small, P. majus Meisn., P. nuttallii Small, 

and P. austiniae Greene. He justified these 

new combinations by the intermediate patterns 

of variation between some of the taxa. 

A sixth species, P. engelmannii Greene was 

put in synonymy under P. douglasii based 

on a previous observation that the two taxa 

are closely related (Hitchcock, 1964) and 

because ‘‘the distinction of these two taxa 

is not always clear’’ (Kartesz & Gandhi, 

1990). The majority of collections annotated 

as ‘‘intermediates’’ by Hickman (in 

CAS, DS, JEPS, RSA, and UC) are either 

between ‘‘P. douglasii subsp. douglasii and 

subsp. johnstonii’’ (P. douglasii and P. sawatchense 

subsp. sawatchense, respectively) 

or between P. douglasii and P. spergulariiforme. 

Most of these ‘‘intermediates’’ 

are, in our opinion, within the range of variation 

of each taxon, which has been poorly 

understood. In the first case, plants regarded 

by Hickman as intermediates between 

‘‘subsp. douglasii and subsp. johnstonii’’ 

are either P. douglasii or P. sawatchense 

subsp. sawatchense (Costea & Tardif, 

2003a). In the second case, most of the 

plants considered by Hickman intermediates 

between P. douglasii and P. spergulariiforme 

belong, in our opinion, to P. majus. 

In most of the situations encountered, 

plants can be assigned to each species using 

qualitative or quantitative characters. Hybridization 

may have played a role in the 

evolution of this group of species, but the 

relatively low levels of introgression observed 

do not warrant their combination in 

a single species. The close relationship between 

these taxa does not justify a cumbersome 

species concept of P. douglasii, to 

which should also be added following the 

same criterion even more species: P. minimum, 

P. cascadense, and P. utahense, as 

well as a previously undescribed species, P. 

gabrielae. This is not the same situation 

within the P. aviculare L. complex, where 

taxa are linked by a continuum transition of 

variation patterns, which makes their recognition 

at species rank unrealistic (Costea 

& Tardif, 2003b). Consequently, a species 

concept closer to that of Small (1895) and 

Hitchcock (1964) is followed here (see also 

the discussions under each species). 

This group of species is probably monophyletic 

and may be worth recognizing as 

a subsection of the section Duravia (emended 

by Hedberg, 1946). Hickman (1984) elevated 

Duravia to the subgenus rank and 

separated from it a new section, Monticola, 

in which he included the species of the P. 

douglasii and P. polygaloides complexes. 

According to this classification, section Duravia 

incorporates species from lowland 

and foothill locations, with leaves not obviously 

jointed to ocreae, linear, 3-nerved 

(rarely 1-nerved), mucronate apex and 

styles separate, hardened, and persistent at 

least at the base. In contrast, Monticola includes 

species from montane areas, with 

leaves obviously jointed to ocreae, apex not 

mucronate, at least lowest leaves lanceolate 

to round and styles, that are fused at base 

and neither hardened nor persistent (Hickman, 

1984). However, we found a considerable 

overlap between Duravia and Monticola 

in these characters. Additionally, 

some species from Duravia cannot be classified 

in any of the two sections (e.g., P. 

shastense Brewer ex A. Gray and P. paronychia 

Cham. & Schlecht.). Therefore, in 

this study, section Duravia is interpreted to 

include section Monticola. The latter section, 

circumscribed here to include only the 

species of P. douglasii complex, may be accepted 

after further study as a subsection of 

Duravia. Some authors (Ronse Decraene & 

Akeroyd, 1988; Ronse Decraene et al., 

2000) suggested that even section Duravia 

is artificial because of the partial overlap in 

floral and fruit characters between some of 

its species and the section Polygonum. Although 

section Duravia is heterogeneous 

and shares some features with section Polygonum 

(Ronse Decraene & Akeroyd, 

1988; Ronse Decraene et al., 2000), the 

morphology of stems, color of anthers, venation 

pattern, structure of petioles (Haraldson, 

1978), and morphology of pollen 

(Hedberg, 1946) clearly separates the two 

sections.

12 BRITTONIA 

[VOL. 57 

Key to the Polygonum douglasii complex 

1. Pedicels patent or erect. 

2. Leaves with one pleat on each side of the midvein --------------------------------------------------------------------------------- P. tenue 

2. Leaves not pleated. 

3. Ocreae 1–4 mm long, funnelform; perianth 1.8–2.5 mm long; achenes 1.8–2.3 mm long. 

4. Plants 1.5–3.5 cm tall; leaves and bracts uniformly papillose, cylindrical due to revolute margins 

that join together on the abaxial face ---------------------------------------------------------------------------------------- P. utahense 

4. Plants 3–50 cm tall; leaves and bracts glabrous or papillose only on the margins; leaves plane 

or with narrow revolute margins, which are never joined together on the abaxial face. 

5. Plants glabrous; flowers wide-open ------------------------------------------------------------------------------------ P. cascadense 

5. Plants papillose-scaberulous at least on the ocreae; flowers closed or semiopen. 

6. Leaves elliptic, obovate to subround, pure green adaxially, margins plane or narrowly 

revolute, irregularly thickened or denticulate-papillose; anthers 120–165 �m long ---- 

-------------------------------------------------------------------------------------------------------------------------------------------- P. minimum 

6. Leaves linear to narrow elliptic, � glaucescent adaxially, margins revolute, smooth; 

anthers 250–325 �m long ---------------------------------------------------------------------------------------------- P. nuttallii 

3. Ocreae 4–12 mm long, not funnelform; perianth 3–5 mm long; achenes 2.5–5 mm long. 

7. Inflorescence dense, cymes crowded and overlapping at stem and branch apices; anthers 

400–550 �m long ---------------------------------------------------------------------------------------------------- P. spergulariiforme 

7. Inflorescence open, cymes regularly spaced along stem and branches; anthers 130–200 �m 

long ----------------------------------------------------------------------------------------------------------------------------------- P. sawatchense 

8. Stems and ocreae glabrous; leaf blades linear to linear-lanceolate, smooth on the margins. 

-------------------------------------------------------------------------------------------------- P. sawatchense subsp. sawatchense 

8. Stems and ocreae scaberulous-papillose; leaf blades elliptic or elliptic-lanceolate, denticulate-papillose 

on the margins --------------------------------------------- P. sawatchense subsp. oblivium 

1. Pedicels reflexed. 

9. Ocreae 6–12 mm long; flowers and achenes 3–5 mm long. 

10. Flowers wide-open or semiopen; pedicels 0.5–1 mm long; perianth tube 9–17% of the 

perianth length; anthers 400–550 �m long -------------------------------------------------------------------------- P. majus 

10. Flowers mostly closed; pedicels 2–6 mm long; perianth tube 20–28% of the perianth length; 

anthers 125–150 �m long ------------------------------------------------------------------------------------------------- P. douglasii 

9. Ocreae 3–5 mm long; flowers and achenes 2–3 mm long. 

11. Inflorescence dense, cymes overlapping at stem and branch apices; flowers wide-open, with 

the tube 10–15% of the perianth length; anthers 325–380 �m long ------------------------ P. gabrielae 

11. Inflorescence elongated, spike-like, cymes spaced along stem and branches; flowers closed, 

with the tube 25–33% of the perianth length; anthers 100–160 �m long. 

12. Tip of mature achene exserted from perianth; lower leaves linear-oblanceolate with 

smooth margins ---------------------------------------------------------------------------------------------------- P. engelmannii 

12. Tip of mature fruit enclosed in perianth; lower leaves broadly elliptic to ovate, with 

margins minutely denticulate-papillose ----------------------------------------------------------------- P. austiniae 

1. POLYGONUM TENUE Michx., Fl. Bor. 

Amer. 1: 238. 1803. TYPE: CANADA. 

‘‘Herbier de l’Amérique septentrionale. 

In Canada, at Mona Caesarea ad Snake 

Bill,’’ Michaux s.n. (LECTOTYPE, here designated: 

P, specimens on left side of 

sheet). 

Polygonum tenue var. protrusum Fernald, Rhodora 

44: 393. 1942. TYPE: United States. Virginia. 

Southhampton Co.: Blackwater River, SE of Ivor, 

16 Oct 1941, Fernald & Long 13937 (HOLOTYPE: 

GH; isotypes: NY, US). 

Annual herbs. Stems 5–50 cm long, 4– 

angled, green or brownish, erect, simple or 

branched, with a few to many branches, upper 

edges glabrous, � winged or denticulate-papillose; 

papillae on the edges (when 

present) conical, 80–120 �m, papillae on 

the stem faces spherical, 7–18 �m, located 

at the same level with the epidermis cells 

(Fig. 1A). Leaves: basal leaves caducous or 

persistent at flowering; upper leaves reduced 

to scale-like bracts upward; ocreae 

6–15 mm, glabrous, free part soon disintegrating 

into a few brown fibers; blades narrowly 

lanceolate to linear, with 2 deep 

pleats parallel to the midvein, 25–40 � 1– 

8 mm, margins usually plane, denticulatepapillose, 

apex mucronate or cuspidate. Papillae 

on leaf margins conic-elongated or 

cylindrical, 110–200 �m. Inflorescences 

terminal, spike-like, slender and elongated; 

cymes 1 or 2(3)-flowered, widely spaced 

along stem and branches; bracts shorter to 

equaling the flowers they subtend. Flowers 

closed; pedicels erect, 1–1.5 mm; perianth


13 

2.5–4.2 mm, the tube 15–22% of the perianth 

length, perianth lobes petaloid or sepaloid, 

cucullate, naviculate, overlapping, 

green (often brownish when dried), with 

pink or white borders; perianth lobe cells 

rectangular, 33–45 � 18–22 �m, with the 

anticlinal walls straight; epicuticular wax 

pattern of type 1, with a transversal pattern 

of rodlets (Fig. 4A). Stamens 8, with pink 

or purple anthers, 125–150 �m long. Pollen 

of subtype A1, 21–24 �m (Fig. 6B). 

Achenes elliptic to oblong, 2.3–4 mm, included 

in the perianth or slightly exserted 

at maturity, smooth or minutely striate-tubercled 

near the edges and apex (Fig. 7C). 

2n � 20 (Löve & Löve, 1956). 

Löve and Löve (1956) reported that they 

obtained fertile hybrids from crosses between 

P. tenue and P. douglasii. This study 

was criticized and its results disregarded because 

authors did not cite any vouchers and 

because some chromosome counts were 

doubtful (e.g., Mertens & Raven, 1965; 

Wolf & McNeill, 1987). However, P. tenue 

is hardly mistakable with any other Polygonum 

species because of its peculiar leaf 

morphology. This is the only species of the 

section Duravia that has evolved in central 

and eastern North America. Its geographical 

distribution (see below) extends westwards 

to Wyoming and overlaps in part 

with that of P. douglasii and P. sawatchense 

subsp. sawatchense. Morphologically 

and micromorphologically the three taxa 

are similar. They have the A1-subtype of 

pollen grains and perianth lobes with epicuticular 

wax organized as transversally 

oriented rodlets. All evidence indicates that 

P. tenue, P. sawatchense, and P. douglasii 

may connect section Duravia to section Polygonum. 

Two geographically distinct collections 

of P. tenue are mounted on the type sheet. 

The left group of specimens are from Canada. 

Because they are mature and more numerous, 

they are here designated as a lectotype. 

The collections from the right are 

from the United States, ‘‘stam. 7, stili 3, in 

pratensibus Illinoesimum.’’ They are immature 

but easily recognizable by the morphology 

of the leaves. 

Distribution and ecology. Canada (southern 

Ontario) and the United States (Ala- 

bama, Arkansas, Connecticut, Delaware, 

District of Columbia, Georgia, Illinois, Indiana, 

Iowa, Kansas, Kentucky, Louisiana, 

southern Maine, Maryland, Massachusetts, 

southern Michigan, southern Minnesota, 

Missouri, Nebraska, New Hampshire, New 

Jersey, New York, western North Carolina, 

Ohio, Oklahoma, Pennsylvania, Rhode Island, 

South Dakota, Tennessee, eastern Texas, 

Vermont, Virginia, West Virginia, southern 

Wisconsin, and Wyoming). It grows on 

dry, sandy, acid soils, in exposed locations. 

Phenology. Flowering June–October. 

2. POLYGONUM DOUGLASII Greene, Bull. Calif, 

Acad. Sci. 1: 125. 1885. TYPE: UNIT- 

ED STATES. California. Tulare Co.: 

Coyote Creek, 30 Jul 1904, Culberson 

4391 (NEOTYPE designated by Hickman 

1984: DS; ISONEOTYPE: NDG). 

Polygonum tenue var. latifolium Engelm. in A. Gray, 

Proc. Acad. Nat. Sci. Philadelphia 1863: 75. 

1863. Polygonum douglasii var. montanum Small, 

Mem. Dept. Bot. Columbia Coll. 1: 118. 1895. 

Polygonum douglasii var. latifolium (Engelm. ex 

A. Gray) Greene, Bull. Calif. Acad. Sci. 1: 125. 

1885. Polygonum montanum (Small) Greene, Pl. 

Baker. 3: 13. 1901. TYPE: not designated. 

Polygonum emaciatum A. Nelson, Bot. Gaz. 54: 

138. 1912. TYPE: UNITED STATES. Idaho. Gem 

Co.: ‘‘doby’’ lava slopes, near Sweet, 14 Aug 

1911, MacBride 1692 (LECTOTYPE, here designated: 

RM; ISOLECTOTYPES: GH, US, WS–n.v. 

Annual herbs. Stems 5–80 cm long, 4angled, 

green, erect to ascendent, simple to 

freely branched from below the middle, glabrous 

with smooth faces, or angles with 

sparse papillae; papillae conical, 40–60 �m 

long. Leaves: basal leaves usually caducous 

or persistent at flowering, upper leaves 

abruptly reduced to scale-like bracts; ocreae 

6–12 mm, glabrous or sparsely scaberulouspapillose, 

with the free part hyaline, lacerate; 

leaf blades linear, narrow-oblong, oblanceolate 

to oblong, 15–55 � 2–8(–12) 

mm, margins smooth or denticulate-papillose; 

apex acute or mucronate. Papillae on 

ocreae and leaf margins are similar to those 

on the stems, or they may be conic-cylindrical, 

60–85 �m long. Inflorescences terminal, 

elongated and spike-like; cymes 2– 

4-flowered, regularly spaced along the stem 

and branches; bracts equaling or somewhat 

longer than the flowers. Flowers closed;

14 BRITTONIA 

[VOL. 57 

pedicels reflexed, 2–6 mm; perianth 3–4.5 

mm, the tube 20–28% of the perianth 

length, perianth lobes petaloid or sepaloid, 

cucullate, naviculate, overlapping, tannish 

to green, margins white or pink, midveins 

usually branched, rarely unbranched (Fig. 

3A); perianth lobe cells rectangular 30–60 

� 9–15 �m with anticlinal walls straight or 

weekly sinuate; epicuticular wax pattern belongs 

to type 1 and has transversally reticulate 

rodlets (Fig. 4B). Stamens 6–8; anthers 

pink to purple, 125–150 �m long. Pollen 

of subtype A1, 22–24 �m (Fig. 6A). 

Achenes elliptic, oblong to ovate, 3–4(– 

4.5) mm, enclosed in the perianth at maturity, 

smooth or tubercled. 

Greene (1885) described P. douglasii var. 

latifolium with ‘‘saw-toothed,’’ oblong 

blades, and oblong achenes, as opposed to 

var. douglasii having linear-lanceolate to 

lanceolate or oblanceolate, glabrous leaves, 

and ovate achenes. This variety has been 

accepted by Hitchcock (1964), but the authors 

abandoned the leaf margin and achene 

shape characters. Indeed, we have encountered 

P. douglasii plants with narrow-lanceolate 

leaves having denticulate-papillose 

margins, as well as plants with glabrous oblong 

leaves. Achene shape also varies from 

elliptic to oblong or ovate, with no relation 

to the blade width. Although plants with 

wide leaves tend to occur more frequently 

at higher altitudes, leaf shape varies continuously, 

and the two varieties cannot be satisfactorily 

separated. Plants with broad 

leaves bring P. douglasii close to P. austiniae 

and to P. sawatchense subsp. oblivium. 

In fact, Hickman (in herb.) regarded such 

plants as intermediates between P. douglasii 

‘‘subsp. johnstonii (P. sawatchense 

subsp. sawatchense) and subsp. douglasii.’’ 

However, P. douglasii is readily distinguished 

from P. austiniae by its bigger 

flowers and achenes. From P. sawatchense 

subsp. oblivium it differs by the glabrous 

stems, reflexed achenes, and the pollen of 

subtype A1. From both taxa, it is distinguished 

by the epicuticular wax sculpture 

of perianth lobes with transversally reticulate 

rodlets. 

Distribution and ecology. Canada (Alberta, 

British Columbia, Saskatchewan, 

Manitoba, Ontario, and Québec) and the 

United States (Arizona, California, Colorado, 

Idaho, Maine, Maryland, Michigan, 

Minnesota, Montana, Nebraska, New York, 

Nevada, New Hampshire, New Mexico, 

New York, North Dakota?, Oregon, South 

Dakota, Utah, Vermont, Virginia, Washington, 

and Wyoming). It grows in dry, montane 

and lowland areas, sometimes disturbed 

places, at elevations ranging from 

500 to 3000 m. 


3. POLYGONUM SAWATCHENSE Small, Bull. 

Torrey Bot. Club 20: 213, pl. 156. 1893. 

TYPE: UNITED STATES (State and 

County not given). Yellowstone Park, 

1885, Tweedy s.n. (NEOTYPE designated 

by Costea & Tardif, 2003a: US). 


green to brownish, simple or 

branched from base, glabrous or scaberulous-papillose. 

Leaves: basal leaves persistent 

or caducous at flowering, upper leaves 

abruptly reduced to scale-like bracts, or 

much longer than the flowers they subtend; 

ocreae 4–12 mm, glabrous or scaberulous 

papillose, free part lacerate or disintegrating 

into a few fibers; blades linear, narrow-oblong 

to oblanceolate or oblong elliptic to 

elliptic, 15–45 � 2–8(–12) mm; margins 

smooth or denticulate-papillose; apex acute 

or mucronate. Inflorescences axillary or terminal, 

long, open spike-like thyrses; cymes 

2–4(–6)-flowered widely spaced along the 

branches; bracts equaling to much longer 

than the flowers they subtend. Flowers 

closed or wide-open; pedicels erect, 1–4 

mm; perianth 2.8–3.5 mm; the tube 20– 

40% of the perianth length, perianth lobes 

petaloid or sepaloid, cucullate, naviculate, 

overlapping, greenish or reddish, with white 

or pink borders; midveins unbranched or 

with a few branches at base. Stamens 3–8; 

anthers pink to purple, rarely whitish, 130– 

200 �m. Pollen of type A. Achenes elliptic, 

2.5–3 mm, enclosed in perianth at maturity, 

smooth. 

The species is variable and two subspecies 

have been recognized (Costea & Tardif, 

2003a). Although the two subspecies 

are distinct, intermediates may occur in the 

areas of sympatry.


15 

POLYGONUM SAWATCHENSE Small subsp. 

SAWATCHENSE 

Polygonum douglasii Greene var. johnstonii Munz, 

Man. So. Calif. Bot. 131: 597. 1935. Polygonum 

douglasii subsp. johnstonii (Munz) J. C. Hickman, 

Madroño 31: 250. 1984. TYPE: UNITED 

STATES. California. San Bernardino Co.: San 

Bernardino Mts., Fish Creek, 2320 m, Munz & 

Johnston 8506 (HOLOTYPE: RSA). 

Polygonum exile Eastw., Proc. Calif. Acad. Ser. 3, 

Bot. 2: 286. 1902. TYPE: UNITED STATES. California 

(County not given). Kings River Canyon, 

4 Jul 1899, Eastwood s.n. (HOLOTYPE: CAS). 

Polygonum triandrous Coolidge, Madroño 20: 266. 

1970. TYPE: UNITED STATES. Idaho. Blaine 

Co.: Hyndman Peak Trail, 13 Aug 1953, Baker 

11005 (HOLOTYPE: ID; ISOTYPES: OSC, UC, WS– 

n.v., WTU–n.v.). 

Stems 4–50 cm long, green to brownish, 

usually branched from base, glabrous, with 

smooth faces (Fig. 1E) and sometimes narrow 

winged angles. Leaves caducous or 

persistent at flowering, upper leaves abruptly 

reduced to scale-like bracts or much longer 

than the flowers they subtend; ocreae 

glabrous; blades linear, narrow-oblong to 

oblanceolate, 15–45 � 2–8(–12) mm; margins 

usually revolute, smooth (Fig. 2A). Inflorescences 

axillary or long, open spikelike 

thyrses; cymes 2–4(–6)-flowered, 

widely spaced along branches; bracts equaling 

or much longer than the flowers. Flowers 

mostly closed; pedicels erect, 1–4 mm, 

perianth (2.8–)3–3.5 mm; the tube 25–40% 

of the perianth length (Fig. 3F), perianth 

lobes greenish or reddish with white or pink 

borders; midveins unbranched or with a few 

branches at base; perianth lobe cells rectangular, 

30–50 � 10–17 �m, with anticlinal 

walls straight or weekly sinuate; epicuticular 

wax pattern of type 1, with reticulate 

rodlets (Fig. 4C), which may sometimes 

be mostly transversally oriented. 

Stamens 3–8; anthers pink to purple, 130– 

160 �m, Pollen of subtype A1, rarely A2, 

21.2–26 �m long (Fig. 6C). Achenes 2.5– 

3 mm. elliptic (Fig. 7A). 


Saskatchewan), the United States 

(Arizona, California, Colorado, Idaho, 

Montana, Nevada, New Mexico, North Dakota, 

South Dakota, Utah, Washington, Wyoming), 

and Mexico (Baja California). It 

grows in dry meadows, pastures, sagebrush 

and forests on sandy, gravelly, or rocky 

substrates. 

Phenology. Flowering June–August. 

POLYGONUM SAWATCHENSE subsp. OBLIVIUM, 

Costea & Tardif, Sida 20: 1637. 2003. 

TYPE: UNITED STATES. California. Siskiyou 

Co.: Salmon Mountains, High 

Lake Basins in the vicinity of English 

Peak, Marble Mountain Wilderness Area, 

gully near meadow SE of Tom Taylor 

Cabin, 2040 m, 13 Aug 1967, Oettinger 

260 (HOLOTYPE: RSA). 

Polygonum douglasii subsp. johnstonii auct. 

Stems 5–15(–25) cm long, green, simple 

or with a few branches from base, scaberulous-papillose 

on and between ribs; papillae 

white, patent, dense, conic-elongated to 

cylindrical, 90–150 �m (Fig. 1D). Leaves 

usually persistent at flowering and gradually 

decreasing in size upwards; ocreae 4– 

10 mm, scaberulous-papillose, with the free 

part lacerate or disintegrating into a few fibers; 

blades elliptic to oblong-elliptic, 8– 

20(–25) � 5–10 mm; margins plane, denticulate-papillose 

(Fig. 2C). Papillae on ocreae 

and leaf margins are similar to those 

present on the stems (Figs. 1D, 2C). Inflorescences 

mostly axillary, or if a terminal 

spike-like thyrse is present, than it is shorter 

than 5 cm; cymes 1 or 2(3)-flowered; bracts 

leaf-like, much longer than the flowers. 

Flowers; at least some of them wide-open; 

pedicels erect, 1–3 mm; perianth 3–4 mm, 

tube 20–30% of the perianth length, perianth 

lobes cucullate, naviculate and overlapping 

(Fig. 3B), greenish white or greenish 

yellow (sometimes flushed with purple), 

with white borders; midveins greenish or 

brown usually branched at base; perianth 

lobe cells elongated, 45–65 � 5–8 �m, with 

the anticlinal walls strongly sinuate; epicuticular 

wax pattern of type 2, with a narrow 

longitudinal pattern of reticulate rodlets at 

the top of cells (Fig. 4D). Anthers pink to 

purple, which rarely may be whitish, 130– 

200 �m. Pollen of subtype A2, 26–29 �m 

(Fig. 6D). Achenes 2.6–3.3 mm, elliptic 

(Fig. 7B). 

This taxon has erroneously been referred 

to as P. douglasii subsp. johnstonii. The latter 

name is based on the epithet of the het-

16 BRITTONIA 

[VOL. 57 

erotypic P. douglasii var. johnstonii that has 

caducous oblong-lanceolate leaves and the 

entire plant is glabrous and more or less 

glaucous. However, such plants are within 

the range of variation of P. sawatchense 

subsp. sawatchense (Costea & Tardif, 

2003a). The stems of P. sawatchense subsp. 

oblivium are scaberulous papillose, the 

leaves are oblong-elliptic to elliptic, papillose 

denticulate on the margins, the flowers, 

at least some of them, are open, and the 

pollen belongs to the subtype A2. Polygonum 

sawatchense subsp. sawatchense is 

glabrous, the leaves are linear to oblanceolate, 

flowers are normally closed, and the 

pollen belongs to subtype A1 or A2. The 

micromorphology of perianth surface of the 

two taxa is also different. Polygonum sawatchense 

subsp. oblivium has perianth 

lobe cells with anticlinal walls strongly sinuated 

and epicuticular wax pattern of type 

2, while subsp. sawatchense has anticlinal 

walls straight or weekly sinuate, and the 

epicuticular wax pattern of type 1. Polygonum 

sawatchense subsp. oblivium has also 

been frequently confused with P. austiniae 

and P. minimum. From P. austiniae it differs 

through its erect and much larger flowers 

and achenes. From P. minimum it is distinguished 

by the morphology of leaves and 

ocreae, stems, size of fruiting perianth and 

achenes, as well as the micromorphology of 

perianth. In particular, P. minimum has 

leaves that are hardly reduced distally, funnelform 

ocreae 1–4 mm long, papillae on 

stems and ocreae are conical, short, with a 

swollen base, and flowers and achenes are 

usually much smaller. 

Distribution and ecology. Western 

Canada (British Columbia) and western 

United States. It has the same ecology as 

subsp. sawatchense but unlike the latter 

may also grow in shaded or moist places. 


4. POLYGONUM ENGELMANNII Greene, Bull. 

Calif. Acad. Sci. 1: 125. 1885. Polygonum 

douglasii subsp. engelmannii 

(Greene) Kartesz & Gandhi, Phytologia 

68: 424. 1990. Polygonum tenue var. microspermum 

Engelm., Proc. Acad. Nat. 

Sci. Philadelphia 1863: 75. 1864. Polygonum 

microspermum Small, Bull. Torrey 

Bot. Club 19: 366. 1892. TYPE: UNITED 

STATES. Colorado. Jefferson Co.: Bergen 

Park, 14 Sep 1877, Greene s.n. (NEO- 

TYPE here designated: NDG). 

Annual herbs. Stems 4–30 cm, green or 

purplish brown, freely branched from base, 

sparsely scaberulous-papillose on the ribs to 

almost glabrous; papillae conical, patent, 

40–60 �m, Leaves: basal leaves persistent 

at flowering, upper leaves abruptly reduced 

to scale-like bracts; ocreae 3–5 mm, funnelform, 

scaberulous-papillose to glabrous, 

free part becoming lacerate with age; blades 

linear-oblanceolate, 10–20(–25) � 1–3(–4) 

mm; margins revolute, smooth; apex acute 

to mucronate. Papillae on the ocreae are 

similar to those present on the stems. Inflorescences 

terminal, elongate spike-like 

thyrses, loose floriferous nearly to base; 

cymes (1–)2–4-flowered, regularly spaced 

along the stems and branches; bracts equaling 

or somewhat longer than the flowers. 

Flowers closed; pedicels reflexed, 1–3 mm; 

perianth 1.5–2(–2.5) mm; tube 18–26% of 

the perianth length, perianth lobes almost 

sepaloid, initially cucullate, later � flat, naviculate, 

forced apart by the developing 

achene (Fig. 3I), greenish or sometimes 

purple, with narrow white margins, midveins 

darker, unbranched; perianth lobe 

cells elongated, 45–65 � 5–8 �m, with the 

anticlinal walls strongly sinuate; epicuticular 


longitudinal pattern of reticulate rodlets at 

the top of cells (Fig. 5C). Stamens 5–8, anthers 

pink to purple, 128–158 �m, Pollen 

of subtype A1, 22.3–23.7 �m. Achenes elliptic, 

1.2–2.3 mm, mostly exserted from 

the perianth at maturity, smooth. 

As in the case of P. nuttallii (see below), 

the collection quoted by Hitchcock (1964) 

is formally typified here. Polygonum engelmannii 

is closely related to P. douglasii and 

P. austiniae. The three species have in common 

reflexed pedicels, short anthers, and 

the A1 subtype of pollen. However, the diminutive 

habit, small, funnelform ocreae, 

fruiting perianth, and achenes distinguish 

the former from P. douglasii. Although it 

may appear similar to P. austiniae, P. engelmannii 

is distinguished by its linear-oblanceolate 

leaves and exserted achenes. Ad-


17 

ditionally, the three species have perianth 

lobes with a different pattern of organization 

of epicuticular waxes (Figs. 4B; 5A, 

C). 


British Columbia) and the United 

States (Colorado, Idaho, Montana, Nevada, 

South Dakota, Utah, and Wyoming). It 

grows in dry to moist, usually sandy or well 

drained soils, sandy gullies in prairie, from 

sagebrush deserts to lower mountains. 

Phenology. Flowering June–September. 

5. POLYGONUM AUSTINIAE Greene, Bull. Calif. 

Acad. Sci. 1: 212. 1885. Polygonum. 

douglasii var. austiniae (Greene) M. E. 

Jones, Contr. West. Bot. 12: 75. 1908. 

Polygonum douglasii subsp. austiniae 

(Greene) A. E. Murray, Kalmia 12: 23. 

1982. TYPE: UNITED STATES. California 

(County not given): Goose Lake Valley, 

1885, Austin s.n. (NEOTYPE designated 

by Hickman, 1984: NDG; ISONEOTYPE: 

US). 

Annual herbs. Stems 5–10(–20) cm, 4angled, 

green to purplish, much branched 

from base, ascending to erect, scaberulouspapillose 

on the ribs; papillae white, conical 

40–60 �m. Leaves: basal leaves usually 

persistent at flowering, upper leaves abruptly 

reduced to scale-like bracts; ocreae 3–5 

mm, funnelform, scaberulous-papillose or 

glabrous, free part lacerate; blades ovate to 

elliptic or obovate, 5–15 � 4–7 mm, margins 

plane or only very narrow revolute, 

denticulate-papillose; apex acute or mucronate. 

Papillae on ocreae and blades are similar 

to those on the stems. Inflorescences; 

lower cymes axillary, upper cymes in slender 

open spike-like thyrse; cymes 1–4flowered, 

regularly spaced along the stems 

and branches; bracts equaling or somewhat 

longer than the flowers. Flowers closed; 

pedicels reflexed, 1–2.5 mm; perianth (1.8– 

)2–2.6 mm, tube 20–28% of the perianth 

length, perianth lobes sepaloid or petaloid, 

cucullate, naviculate, overlapping (Fig. 3J), 

green or purple, with narrow, whitish margins; 

midveins darker, unbranched; perianth 

lobe cells elongated, irregularly branched to 

almost rectangular, 35–60 � 8–16 �m, with 

anticlinal walls moderately sinuate to al- 

most straight; epicuticular wax pattern of 

type 2, with a dense pattern of intertwined 

rodlets at the top of cells (Fig. 5A). Stamens 

8, anthers pink to purple, 130–160 

�m. Pollen of subtype A1, 20.1–23.3 �m. 

Achenes elliptic to slightly obovate, 2–2.5 

mm, enclosed in the perianth at maturity, 

smooth or nearly so (Fig. 7G). 


Canada (Alberta, British Columbia) and 

western United States. It grows in dry to 

moist flats on banks; from sagebrush plains 

to lower mountains, often in Ponderosa pine 

forests. 


6. POLYGONUM MINIMUM S. Watson, Bot. 

King Exp. 315. 1871. TYPE: UNITED 

STATES. Utah. Box Elder Co.: Bear 

River Canyon, 3200 m, Aug 1869, Watson 

1058 (HOLOTYPE: US; ISOTYPES: NY, 

GH). 

Polygonum torreyi S. Watson, Amer. Nat. 7: 664. 

1873. TYPE: UNITED STATES. California. Mariposa 

Co.: Yosemite Valley, 1872, Torrey s.n. (HO- 

LOTYPE: GH). 


reddish brown, wiry, prostrate to 

erect, often zigzagged, simple or branched 

from base, scaberulous-papillose on and between 

the ribs; papillae red, orange or 

sometimes white, patent, conical with a 

swollen base, 40–60 �m (Fig. 1B). Leaves 

persistent at flowering, evenly distributed or 

crowded at branch tips, hardly reduced distally; 

ocreae funnelform, 1–4 mm, scaberulous-papillose, 

free part entire or dentatelacerate; 

blades narrow-elliptic, elliptic, 

ovate, obovate, or subcircular, 6–27 � 3–8 

mm; margins plane, irregularly thickened or 

denticulate-papillose (rarely glabrous), apex 

acute or mucronate. Papillae on the ocreae 

are often retrorse, similar to those on the 

stem; papillae on the leaf margins are white, 

conic-cylindrical, 100–180 �m, Inflorescences 

axillary; cymes 1–3-flowered starting 

from near stem and branch bases, sometimes 

also crowded at branch apices; bracts 

leaf-like, much longer than the flowers they 

subtend. Flowers semiopen or closed; pedicels 

erect to patent, 2–3 mm; perianth 1.8– 

2.5 mm; tube 22–29% of the perianth 

length; perianth lobes almost sepaloid, cu-

18 BRITTONIA 

[VOL. 57 

cullate, naviculate to obscurely so, overlapping, 

green with narrow white or pink margins, 

midveins thickened, unbranched; perianth 

lobe cells are irregularly shaped, 35– 

45 � 10–16 �m with the anticlinal walls 

moderately sinuate; epicuticular wax pattern 

of type 1, with a dense pattern of reticulate 

and intertwined rodlets (Fig. 5E). 

Stamens 8; anthers purple, 120–165 �m. 

Pollen of subtype A2, 26–28.2 �m (Fig. 

6E). Achenes elliptic to ovate, 1.8–2.3 mm, 

enclosed in the perianth at maturity, or only 

with the tip exserted, smooth. 

Although obviously related to P. douglasii, 

the specific status of P. minimum has 

never been questioned as it has been for 

other similarly related species. The morphology 

of anthers and pollen place P. minimum 

in close relationship to P. sawatchense 

subsp. oblivium, P. douglasii, P. engelmannii 

and P. austiniae. Some forms 

with narrow leaves approach P. nuttallii, 

with which P. minimum shares a common 

morphology of stems, ocreae, papillae, and 

pattern of epicuticular wax sculpture of 

perianth lobes. However, leaves of P. minimum 

are not glaucous adaxially, the margins 

are plane and denticulate-papillose, the 

flowers are mostly closed, and the pollen 

belongs to type A. 


British Columbia) and the United 

States (Alaska, California, Colorado, Idaho, 

Montana, Nevada, Oregon, Utah, Washington, 

and Wyoming). It grows in alpine to 

subalpine communities, on open or semibarren 

soil; 1500–3300 m. 

Phenology. Flowering July–September. 

7. POLYGONUM NUTTALLII Small, Monogr. 

Polygonum 132, pl. 53. 1895. Polygonum 

intermedium Nutt. ex S. Watson, 

Proc. Amer. Acad. Arts 17: 378. 1882. 

Polygonum douglasii subsp. nuttallii 

(Small) J. C. Hickman, Madroño 31: 250. 

1984. TYPE: UNITED STATES. Oregon 

(County not given). On bluffs of Columbia 

River, Oct 1891, Pringle s.n. (LEC- 

TOTYPE, here designated: GH; ISOLECTO- 

TYPE: NY). 

Annual herbs. Stems (5–)10–35 cm long, 

4-angled, purplish, wiry, sometimes zig- 

zagged, simple or branched, spreading to 

erect, scaberulous-papillose on and between 

the ribs (Fig. 1F); papillae red, orange or 

sometimes white, patent or retrorse, conical 

with a swollen base, 40–60 �m. Leaves: 

basal leaves persistent at flowering, evenly 

distributed or crowded at branch tips, gradually 

transformed into bracts; ocreae 3–4 

mm long, funnelform, scaberulous-papillose, 

free part finally lacerate; blades linear 

to narrow-elliptic, 8–30 � 1–4(–7) mm, � 

glaucous adaxially; margins revolute, 

smooth; apex acute or acuminate. Papillae 

on ocreae are often retrorse, similar to those 

on the stems (Fig. 1F). Inflorescences terminal, 

spiciform, dense and bracted; cymes 

with 2–3 flowers, aggregated at the apices 

of branches; bracts much longer than the 

flowers they subtend. Flowers semiopen or 

closed; pedicels erect or patent, 2–3 mm; 

perianth 1.8–2.4 mm; tube 25–33% of the 

perianth length, perianth lobes petaloid, cucullate, 

usually naviculate only in the upper 

1/4, � overlapping (Fig. 3C), pinkish green 

with pink borders, midvein greenish, unbranched; 

perianth lobe cells rectangular or 

irregularly shaped, 35–45 � 10–16 �m 

with anticlinal walls moderately sinuate; 

epicuticular wax pattern of type 1, with a 

dense pattern of reticulate and intertwined 

rodlets (Fig. 5F). Stamens 8; anthers purple, 

250–325 �m. Pollen of type B, 27–29.2 �m 

(Fig. 6F). Achenes elliptic to ovate, 1.8–2.3 

mm, enclosed in perianth at maturity, 

smooth. 

Polygonum intermedium is illegitimate 

being a latter homonym for which Small 

(1895) proposed a new name, P. nuttallii. 

The collection designated as a lectotype 

was first quoted by Hitchcock (1964). Hickman 

(1984) considered that Hitchcock effectively 

lectotypified Polygonum nuttallii. 

However, in Vascular Plants of the Pacific 

Northwest, no names were typified unless 

specifically stated (Hitchcock et al., 1957). 

To eliminate any doubt, the lectotype was 

formally designed here. 

This distinct but uncommon species has 

been combined with P. douglasii (Hickman, 

1984) because it was considered a 

small-flowered form of P. spergulariiforme, 

as previously suggested by Hitchcock 

(1964). Although similar to P. spergulari-


19 

iforme, P. nuttallii differs from the former 

in many respects: the stems are purplish and 

wiry, the ocreae are short with conical and 

swollen at base papillae, leaves are glaucous 

adaxially, bracts are much longer than 

flowers, and the fruiting perianth and 

achenes are short. Anticlinal walls of perianth 

lobe cells are moderately sinuate and 

the epicuticular wax pattern belongs to type 

1. Polygonum nuttallii has a common morphology 

of stems, ocreae, papillae, and surface 

of perianth lobes with P. minimum. 


Canada and western United States. It grows 

in dry ‘‘prairies’’ and open knolls in lower 

mountains, open sites in lowland and montane 

zones, sandy soil at low elevations. 

Phenology. Flowering May–October. 

8. POLYGONUM SPERGULARIIFORME Meisn. ex 

Small, Bull. Torrey Bot. Club 19: 366. 

1892. Polygonum coarctatum Douglas ex 

J. M. Hook. var. minus Meisn. in DC., 

Prodr. 14: 101. 1856. Polygonum douglasii 

subsp. spergulariiforme (Meisn. ex 

Small) J. C. Hickman, Madroño 31: 251. 

1984. TYPE: UNITED STATES (Washington 

or Oregon). Hab. N.W. America. 

On the sandy banks of the Columbia and 

its branches, and on the higher branches 

of the Multnomak, Menzies s.n. (LECTO- 

TYPE designated by Hickman, 1984: K– 

n.v.). 


green, divaricately branched, scaberulous 

on and between ribs (Fig. 1C) 

(rarely almost glabrous); papillae white, 

patent, dense, conical-elongate to cylindrical, 

100–200 �m. Leaves: basal leaves usually 

caducous at flowering, upper leaves 


8–12 mm, scaberulous-papillose, free part 

disintegrating into a few persistent fibers; 

blades linear to lanceolate, 35–60 � 1–3 

mm, sometimes with scarce papillae (Fig. 

2E); margins plane or very narrowly revolute, 

denticulate-papillose; apex acute or 

mucronate. Papillae on the ocreae and the 

margins of leaves are similar to those on 

the stems (Fig. 1C); papillae from the leaf 

blade are conical, shorter, 40–60 �m, with 

a heavy cuticle (Fig. 2E). Inflorescences 

terminal, spiciform, dense; cymes 2–5flowered, 

crowded and � overlapping at 

branch tips; bracts equaling or somewhat 

longer than the flowers. Flowers open or 

semiopen; pedicel patent to erect, to 2 mm; 

perianth 3–5 mm, tube 9–17% of the perianth 

length, perianth lobes petaloid, cucullate, 

usually naviculate only in the upper 1/ 

4 part, overlapping, pink or white, with 

broad pink borders; midveins green or 

brown, with short lateral branches; perianth 

lobe cells elongated, 50–65 � 6–9 �m with 

the anticlinal walls strongly sinuate; epicuticular 


pattern of reticulate rodlets at the top of 

cells (Fig. 4E). Stamens 8, anthers pink to 

purple, 400–550 �m. Pollen of type B, 31– 

33 �m. Achenes narrow elliptic to elliptic 

lanceolate, 3–5 mm, enclosed in the perianth 

at maturity, smooth or tubercled (Fig. 

7F). 

Plants with cymes spaced along the 

branches (not aggregated at branch apices) 

and the flowers more or less patent or ascendent 

may be intermediates to P. majus, 

the closest related taxon. However, the reflexed 

achenes of the latter clearly separate 

the two taxa. Specimens annotated by Hickman 

(in herb.) as ‘‘intermediate between 

subsp. spergulariiforme and subsp. douglasii’’ 

belong to P. majus. 

Distribution and ecology. Canada 

(southern British Columbia) and western 

United States. It grows in moist to dry, 

open rocky places (including serpentine); 

10–2000 m. 


9. POLYGONUM MAJUS (Meisn.) Piper, Fl. Palouse 

Reg. 63. 1901. Polygonum coarctatum 

Douglas ex Meisn. var. majus 

Meisn. in DC., Prodr. 14: 101. 1856. Polygonum 

douglasii subsp. majus (Meisn.) 

J. C. Hickman, Madroño 31: 250. 1984. 

TYPE: UNITED STATES (Washington or 

Oregon). ‘‘Columbia River,’’ 1830, 

Douglas s.n. (LECTOTYPE designated by 

Hickman, 1984: GDC-n.v.; ISOLECTOTY- 

PE: NY). 


green, erect, simply to freely 

branched, scaberulous-papillose on and be-

20 BRITTONIA 

[VOL. 57 

tween ribs; papillae white, patent or reflexed, 

dense, conical-elongate to cylindrical, 

100–200 �m. Leaves: basal leaves often 

caducous at flowering, upper leaves 


6–12 mm, scaberulous-papillose, free part 

lacerate or disintegrating into fibers; blades 

linear to narrowly oblong or lanceolate, 15– 

70 � 2–8 mm; margins narrowly revolute, 

denticulate-papillose; apex acute or mucronate; 

papillae on the ocreae and leaf margins 

are similar to those on the stems. Inflorescences 

terminal, spike-like, open 

thyrses; cymes 2–5-flowered � uniformly 

spaced on stems and branches; bracts equaling 

or somewhat longer than the flowers. 

Flowers wide-open or semiopen; pedicels 

patent in flower and reflexed in fruit, 0.5– 

1 mm; perianth (3.5–)4–5 mm; tube 9–17% 

of the perianth length, perianth lobes petaloid, 

cucullate, naviculate only in the upper 

1/4 part, overlapping, white or pink, 

borders white to pink; midveins green, unbranched 

or with short lateral branches; 

perianth lobe cells elongated, 45–60 � 6–9 

�m, with the anticlinal walls strongly sinuate; 

epicuticular wax pattern of type 2, 

with a dense intertwined pattern of reticulate 

rodlets at the top of cells (Fig. 4F). Stamens 

8, anthers pink to purple, 400–500 

�m. Pollen of type B, 31–33 �m (Fig. 6H). 

Achenes elliptic, 3.5–5 mm, enclosed in 

perianth at maturity, smooth or tubercled 

(Fig. 7E). 

Distribution and ecology. Canada 

(southern British Columbia) and western 

United States. It grows in dry plains, meadows 

(including serpentine) at elevations of 

500–2000 m. 

Phenology. Flowering May–August. 

10. Polygonum gabrielae Costea & Tardif, 

sp. nov. (Fig. 8) TYPE: UNITED 

STATES. Oregon. Grant Co.: 7 mi S of 

Mt. Vernon, dry, barren, gravelly, northfacing 

serpentine slopes, overlooking 

Laycock Creek, T14S, R30E, S26, 1370 

m, 29 Jun 1953, Cronquist 7330 (HOLO- 

TYPE: NY; ISOTYPES: MICH, MT, OSC, 

RSA, UC, WS). 

Annuum; caulis glaber, erectus, 3–10 cm 

altus; folia oblanceolata vel obovata, 8–20 

mm longa; inflorescentia terminalis densissima, 

2–5 floribus axillaribus, pedicellis reflexis, 

perianthium album, stamina 8; 

achaenia 1.8–2 mm longa, elliptica, inclusa 

vel paulo exserta. Differt a P. cascadense 

bracteis brevioribus paucioribus et pedicellis 

reflexis; difert a P. austiniae inflorescentia 

densissima, spiciformi, floribus apertis, 

perianthio albo, antheris longioribus. 


reddish green erect, zigzagged, 

branched below the middle, � glabrous. 

Leaves: basal leaves persistent at flowering, 

upper leaves gradually transformed into a 

few bracts; ocreae 2–5 mm, funnelform, 

glabrous, free part hyaline � lacerate; 

blades oblanceolate, spathulate or obovate, 

8–20 � 3–4.5 mm, margins plane or very 

narrowly revolute, smooth, apex acute to 

mucronate. Inflorescences terminal, spiciform, 

dense; cymes 2–5-flowered aggregated 

and overlapping at stem and branch apices; 

bracts scarce, shorter or equaling the 

flowers they subtend. Flowers wide-open 

(Fig. 3D); pedicels 0.5–2 mm, patent at 

flowering and reflexed in fruit; perianth 

2.2–2.6 mm, tube 8–15% of the perianth 

length; perianth lobes petaloid, cucullate, 

naviculate, parallel (Fig. 3E), pure white, 

with green unbranched mid-veins (which 

may be brownish on dried material); perianth 

lobe cells are elongated, 55–65 � 8– 

12 �m, with the anticlinal walls strongly 

sinuate; epicuticular wax pattern of type 2, 

with a dense pattern of intertwined rodlets 

interrupted by small unsculputured spaces 

at the top of cells (Fig. 5D). Stamens 8, 

anthers purple, 325–380 �m. Pollen of type 

B, 27.4–30.1 �m (Fig. 6G). Achenes elliptic, 

1.8–2 mm, enclosed or slightly exserted 

from the perianth at maturity, smooth (Fig. 

7I). 

Hickman (in herb.) identified collections 

of P. gabrielae as ‘‘P. cascadense with 

characteristics of P. douglasii.’’ Although 

distinct, P. gabrielae shares some features 

with P. austiniae and P. cascadense; however, 

it differs by a dense terminal inflorescence 

with overlapping cymes, wide-open 

flowers with white perianth lobes, anthers 

over 300 �m long, and pollen of type B. In 

contrast, P. austiniae has an open, elongated 

inflorescence with widely spaced cymes,


21 

FIG. 8. Polygonum gabrielae, general habit (from Cronquist 7330, NY). 

closed flowers, green or purple perianth 

lobes with narrow whitish margins, anthers 

shorter than 160 �m, and pollen grains of 

type A. Polygonum gabrielae is easily distinguished 

from P. cascadense by the few 

and short bracts, perianth lobes naviculate 

along their entire length, and reflexed pedicels. 

The pattern of epicuticular wax sculpture 

in P. gabrielae is singular among the 

other species of Polygonum studied (Fig. 

5D). 

The species is named after Gabriela Costea, 

the senior author’s wife. 

Distribution and ecology. United States 

(rare in Oregon). Growing in dry, barren, 

gravelly serpentine slopes. More research 

will have to determine its exact distribution. 


11. POLYGONUM CASCADENSE W. H. Baker, 

Madroño 10: 62. 1949. TYPE: UNITED 

STATES. Oregon. Lane Co.: Calapooya

22 BRITTONIA 

[VOL. 57 

Range, Fairview Mountain, S slope, 

1670 m, 28 Sep 1947, Baker 5129 (HO- 

LOTYPE: OSC n.v.; ISOTYPES: CAS, US, 

NY, WS). 

Annual herbs. Stems 5–12(–15) cm long, 

4-angled, green, wiry, zigzagged, angled, 

simple or branched from base, glabrous. 

Leaves: basal leaves persistent at flowering 

and gradually transformed into bracts; ocreae 

2–5 mm, glabrous, free part is lacerate; 

blades oblanceolate to obovate, 5–20 � 2– 

5 mm; margins revolute, smooth; apex is 

rounded or mucronate. Inflorescences terminal, 

spiciform, bracteate, dense; cymes 

3–5-flowered, congested at the tip of stems 

and branches; bracts numerous, much longer 

than the flowers. Flowers wide-open; 

pedicels erect to patent, 2–3 mm; perianth 

2–2.5 mm, tube 12–25% of the perianth 

length, perianth lobes petaloid, oblong to 

oblong-obovate, cucullate, naviculate only 

in the upper ¼, overlapping (Fig. 3H), purewhite, 

midveins pink or greenish, unbranched; 

perianth lobe cells irregularly 

branched, 20–35 � 18–26 �m, with anticlinal 

walls strongly sinuate; epicuticular 

wax pattern of type 1, with a dense pattern 

of intertwined, reticulate rodlets. Stamens 

8; anthers purple, 325–350 �m. Pollen of 

type B, 27.3–29.1 �m. Achenes ovate to 

oblong-ovate, 1.8–2.1 mm, included or 

slightly exserted from the perianth at maturity, 

smooth. 


(rare in the Cascade Mountains of Oregon). 

It grows on dry, usually rocky slopes, to 

1800 m, often on serpentine. 


12. POLYGONUM UTAHENSE Brenckle & Cottam, 

Bull. Univ. Utah 30: 3. 1940. Polygonum 

douglasii var. utahense (Brenckle 

& Cottam) S. Welsh, Utah Flora 3rd 

ed.: 518. 2003. TYPE: UNITED STATES. 

Utah. Garfield Co.: Escalante, 17 Sep 

1935, Cottam 6507 (HOLOTYPE: UT; ISO- 

TYPES: CAS, US, NY). 

Dwarf annual herb. Stems 1.5–3.5 cm 

long, 4-angled, erect, simple or with a few 

branches, papillose. Leaves 1–3, persistent 

at flowering; ocreae 2–3.5 mm, papillosescaberulous; 

free part hyaline, lacerate; leaf 

blades erect, linear-subulate, coriaceous, 

uniformly papillose, 6–14 � 1 mm, � cylindrical 

due to revolute margins that join 

together on the lower side of lamina (Fig. 

2B); apex mucronate. Papillae on stems and 

leaves are short, conical, 25–40 �m (Fig. 

2F). Inflorescences are terminal, spiciform, 

bracteate, dense; cymes 2–4-flowered, starting 

almost from stem base, overlapping; 

bracts much longer than the flowers. Flowers 

wide-open; pedicels erect, 0.4–1 mm; 

perianth 2–2.5 mm, tube 20–25% of the 

perianth length; perianth lobes petaloid, oblong 

to wide obovate, cucullate, naviculate 

only in the upper ¼, overlapping (Fig. 3G); 

pure white, midvein green or brownish, 

branched; perianth lobe cells elongated, 55– 

70 � 8–11 �m, with anticlinal walls strongly 

sinuate; epicuticular wax pattern of type 

2, with a dense pattern of intertwined rodlets 

at the top of cells (Fig. 5B). Stamens 

8, anthers purple to dark-brown, 350–420 

�m. Pollen of type B, 27.5–28.9 �m. 

Achenes 1.5–2 mm, elliptic, included in the 

perianth, smooth (Fig. 7J). 

Polygonum utahense has been considered 

a synonym of P. sawatchense subsp. sawatchense 

(e.g., Welsh, 1987; Kartesz, 

1998). Recently it has been combined with 

P. douglasii as a variety (Welsh, 2003). 

However, the morphology of perianth, anthers, 

and pollen place it more closely to P. 

cascadense, from which it is distinguished 

by the dwarf habit and the papillose ocreae, 

stems, and cylindrical leaves. 


(known only from Garfield Co., Utah). 

Growing in dry, sandy ravines, to 2300 m, 

on rocky Navajo sandstone spur. 

Phenology. Flowering July–September. 

Discussion 

The 12 species can be usually clearly 

separated using morphological characters. 

Morphology of achenes, which is so important 

for the species of section Polygonum, 

is less significant for the relatives of 

P. douglasii. Micromorphological characters 

bring in new data that support the recognition 

of the members of P. douglasii 

complex as species. Hong and Oh (1999) 

reported that section Duravia is character-


23 

ized by leaf epidermal cells with undulate 

anticlinal walls, and our study confirms this 

finding. Micromorphology of leaf epicuticular 

wax has little taxonomic significance 

and is useful only in P. utahense, which 

exhibits a pattern of reticulate rodlets. Papillae 

are common structures encountered 

on stems and leaves of these species. Their 

presence or absence, and sometimes their 

morphology, is useful to distinguish some 

taxa. 

The surface of perianth lobes has proven 

to be interesting because in another study, 

Hong et al. (1998) found that ‘‘cuticular 

striation alone does not appear to have 

much systematic value’’ in the tribes Polygoneae 

and Persicarieae. However, the authors 

studied only two species (and two collections) 

from this group (P. douglasii and 

P. spergulariiforme). Our results indicate 

that except for P. majus–P. spergulariiforme 

and P. minimum–P. nuttallii, which are 

very similar in this respect, the other taxa 

are quite distinct. Indeed, the micromorphology 

of perianth lobes surface is remarkably 

diverse and allows the distinction 

of most taxa. 

Hedberg (1946) suggested that the ‘‘Duravia 

type of pollen is derived from the Avicularia-type,’’ 

and that this type of pollen 

evolved independently in Polygonum and 

Polygonella. In this respect, the subtype A1 

of pollen may considered the most primitive 

form of Duravia pollen because it is 

morphologically the closest to the Avicularia-type. 

Pollen of subtype A2 may be 

considered intermediate to the ‘‘typical’’ 

Duravia-type (type B). Plants are self-pollinating, 

but differences in floral and pollen 

morphology suggest that different species 

may have developed different pollination 

strategies. Based on the morphology of 

flowers, anthers and pollen, two directions 

of evolution may be recognized: 

The first, the ‘‘douglasii group’’ (P. 

douglasii, P. sawatchense, P. engelmannii, 

P. austiniae, and P. minimum) has flowers 

usually closed (but sometimes open), anthers 

90–190 �m, and pollen of type A. The 

second, the ‘‘majus group’’ (P. majus, P. 

spergulariiforme, P. nuttallii, P. cascadense, 

P. gabrielae, and P. utahense) has 

flowers open, anthers 250–450 �m, and 

pollen of type B. These two groups overlap 

slightly. For example, P. majus is related to 

P. douglasii and P. spergulariiforme; P. 

nuttallii shares affinities with both P. minimum 

and P. spergulariiforme; P. gabrielae 

is related to both P. austiniae and P. cascadense. 

It may be possible that the evolution 

of these species has been, at lest to 

some extent, reticulate. However, no matter 

how these taxa evolved, the current evidence 

supports their treatment as species. 

Acknowledgments 

We are indebted to Guy Nesom and one 

anonymous reviewer who contributed with 

helpful criticism and suggestions that improved 

earlier versions of the manuscript. 

We thank curators from the herbaria cited 

for preparing the (usually) voluminous 

loans. We are grateful to Sandy Smith who 

facilitated the SEM study. Barbara Hellenthal 

and Cécile Aupic helped us to locate 

some of the type collections. 

Literature Cited 

Barthlott, W., C. Neinhuis, D. Cutler, F. Ditsch, I. 

Meusel, I. Theisen & H. Wilhelmi. 1998. Classification 

and terminology of plant epicuticular waxes. 

Bot. J. Linn. Soc. 126: 237–260. 

Costea, M. & F. J. Tardif. 2003a. Typification, taxonomy 

and a new subspecies of Polygonum sawatchense 

(Polygonaceae) from North America. 

Sida 20: 1631–1640. 

———. 2003b. Nomenclatural changes in the genus 

Polygonum s.str. (Polygonaceae). Sida 20: 987– 

997. 

Haraldson, K. 1978. Anatomy and taxonomy in Polygonaceae, 

subfam. Polygonoideae Meisn. emend 

Jaretzky. Acta Univ. Upsaliensis 22: 1–95. 

Hedberg, O. 1946. Pollen morphology in the genus 

Polygonum L. s. lat. and its taxonomical significance. 

Svensk Bot. Tidskr. 40: 371–404. 

Hickman, J. C. 1984. Nomenclatural changes in Persicaria, 

Polygonum and Rumex (Polygonaceae). 

Madroño 31: 249–252. 

———. 1993. Polygonaceae. Pages 854–895. In: J. C. 

Hickman, editor. The Jepson manual: higher plants 

of California. University of California Press, 

Berkeley, California. 

Hitchcock, C. L., A. Cronquist & M. Ownbey. 1957. 

Vascular plants of the Pacific Northwest. Part 1. 

Cryptogams, Gymnosperms and Monocotyledons. 

University of Washington Press, Seattle, Washington. 

Hitchcock, C. L. 1964. Polygonum. Pages 140–168. 

In: C. L. Hitchcock, A. Cronquist, M. Ownbey & 

J. W. Thompson, editors. Vascular Plants of the Pacific 

Northwest. Part 2. Salicaceae to Saxifraga-

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ceae, University of Washington Press, Seattle, 

Washington. 

Hoen, P. 1999. Glossary of pollen and spore terminology. 

Laboratory of Palaeobotany and Palynology, 

Utrecht. http://www.bio.uu.nl/�palaeo/glossary/glos-int.htm 

Hong, S.-P., L. P. Ronse Decraene & E. Smets. 

1998. Systematic significance of tepal surface morphology 

in tribes Persicarieae and Polygoneae (Polygonaceae). 

Bot. J. Linn. Soc. 127: 91–116. 

Hong, S.-P. & I. C. Oh. 1999. The taxonomic study 

of leaf epidermal microstructure in the genera Polygonum 

s.str. and Polygonella Michx. (Polygonaceae). 

Korean J. Pl. Tax. 29: 75–90. 

Kartesz, J. T. & K. N. Gandhi. 1990. Nomenclatural 

notes for the North American flora II. Phytologia 

68: 421–427. 

Kartesz, J. T. 1998. A synonymized checklist of the 

vascular flora of the United States, Puerto Rico, and 

the Virgin Islands. Full Text Index. http:// 

www.csdl.tamu.edu/FLORA/b98/check98.htm 

Löve, Á. & D. Löve. 1956. Chromosomes and taxonomy 

of eastern North American Polygonum. 

Can. J. Bot. 34: 501–521. 

Mertens, T. R. & P. H. Raven. 1965. Taxonomy of 

Polygonum section Polygonum (Avicularia) in 

North America. Madroño 18: 85–92. 

1. Polygonum tenue. UNITED STATES. 

Connecticut. Middlesex Co.: Portland, 

Bucktown, 4 Sep 1896, Starmer s.n. (NY). 

Illinois. Mason Co.: Near Havana, 15 Sep 

1929, Chase s.n. (DS); Putnam Co.: SE Putnam, 

5 Sep 1949, Chase 10827 (NY). Iowa. 

Allamakee Co.: Iowa Township, 3 mi E of 

New Albin, 13 Sep 1937, Hayden 5028 

(NY). Massachusetts. Middlesex Co.: Woburn, 

Horn Pond Hill, 11 Oct 1935, Smith 

& Hodgdon s.n. (DS). New Jersey. Ocean 

Co.: Forked River, 18 Sep 1932, Alexander 

s.n. (NY). Ohio. Lucas Co.: N of Crissey, 

junction of Frankfort and Meilke Roads, 25 

Jul 1995, Cusick 32610 & Schneider (NY). 

Pennsylvania. Lancaster Co.: Conewago, 1 

Sep 1892, Heller s.n. (NY). South Dakota. 

Minnehaha Co.: Minnehaha, Dell Rapids, 

24 Aug 1946, Brenckle s.n. (CAS). Tennessee. 

Grundy Co.: ca. 10 mi N of Tracy 

City, junction Tennessee 56 and 108, 29 

Sep 1971, Kral 44537 (NY). Wisconsin. 

Richland Co.: 2 mi W of Blue River, 205 

m, 12 Aug 1977, Nee 15698 (NY); Waushara 

Co.: 2 mi W of Coloma, 22 Aug 

1940, Shinners & Catenhusen 2657 (NY). 

2. Polygonum douglasii. CANADA. 

Appendix 1. Vouchers for the SEM Study 

Ronse Decraene, L. P. & J. R. Akeroyd. 1988. Generic 

limits in Polygonum and related genera (Polygonaceae) 

on the basis of floral characters. Bot. 

J. Linn. Soc. 98: 321–371. 

———, S.-P. Hong & E. Smets. 2000. Systematic 

significance of fruit morphology and anatomy in 

tribes Persicarieae and Polygoneae (Polygonaceae). 

Bot. J. Linn. Soc. 134: 301–337. 

Small, J. K. 1895. A monograph of the North American 

species of the genus Polygonum. Lancaster, 

Pennsylvania. 

Welsh, S. L. 1987. Polygonaceae. Pages 470–493. In: 

S. L. Welsh, A. D. Atwood, S. Goorich & L. C. 

Higgins, editors. A Utah flora. Great Basin Nat. 

Mem. 9: 1–894. Brigham Young University, Provo, 

Utah. 

———. 2003. Polygonaceae. Pages 497–521. In: S.L. 

Welsh, N. D. Atwood, S. Goodrich & L. C. Higgins, 

editors. A Utah flora (3rd ed., revised). Marcus 

Jones Endowment Fund, Brigham Young University, 

Provo, Utah. 

Wolf, S. J. & J. McNeill. 1986. Synopsis and achene 

morphology of Polygonum section Polygonum (Polygonaceae) 

in Canada. Rhodora 88: 457–479. 

——— & ———. 1987. Cytotaxonomic studies on 

Polygonum section Polygonum in eastern Canada 

and the adjacent United States. Can. J. Bot. 65: 

647–652. 

Saskatchewan. Grassland National Park: 10 

mi SE of Val Marie, 17 Jul 1989, Hooper 

& Ledingham 10836 (USAS); Cypress 

Hills, Center Block, 29 Aug 1987, Hudson 

4765 (USAS). UNITED STATES. California. 

Eldorado Co.: near Camp Echo, Lincoln 

Hyw., 2130 m, 6 Aug 1915, Heller 

12188 (GH). Montana. Glacier Co.: Glacier 

National Park, vicinity of Belton (now 

called West Glacier), 946–980 m, 3–4 Sep 

1919, Standley 18705 (NY). New Hampshire. 

Caroll Co.: Albany, Santa Moat Mt., 

11 Sep 1949, Seele s.n. (GH); Coös Co.: 

Hart’s Ledge, Hadley’s Grant, 9 Sep 1915, 

Pease s.n. (NEBC in GH). Oregon. Baker 

Co.: Blue Mts., S side of meadows about 

Mud Lake, Anthony Lakes, Elkhorn Ridge, 

9 Aug 1946, Maguire & Holmgren s.n. 

(NY). Utah: (County not given) Elk Mts., 

near Scorup’s Camp, 2500 m, 8 Aug 1911, 

Rydberg & Garrett 9553 (NY). Vermont. 

Addison Co.: Addison, Snake Man, 1878, 

Brainerd s.n. (GH); Rutland Co.: W of Rutland, 

12 Sep 1912, Kirk s.n. (NEBC in 

GH). 

3a. Polygonum sawatchense Small 

subsp. sawatchense. UNITED STATES.


25 

Arizona. Coconino Co.: Buch Springs 

Ranger Station, 2290 m, Sep 1936, Collom 

599 (US); Flagstaff, 2 Aug 1884, Jones 

3957 (RSA); Cochise Co.: Chiricahua Mts., 

Coronado National Forest, S base of Barfoot 

Peak, 2500 m, 4 Sep 1983, Ward & 

Peterson s.n. (RSA). California. Lassen 

Co.: Harvey Valley, 9 Jul 1934, Howell 

12528 (RSA); Riverside Co.: Santa Rosa 

Peak, Virgin Springs, 2290 m, 14 Aug 

1938, Munz 15359 (RSA); San Bernardino 

Co.: San Bernardino Mts., bellow Dollar 

Lake, 2650 m, 22 Aug 1922, Munz 6190 

(RSA). Colorado. Conejos Co.: 7 mi N of 

Conejos Campground, NW of Antonito, 19 

Jul 1952, Weber 7862 (RSA); Larimer Co.: 

Moraine Park, 11 Aug 1925, Osterhout 

6464 (RSA). Nevada. Clark Co.: Charleston 

Mts., Charleston Park, 2270 m, 29 Jul 1938, 

Clokey 7901 (RSA); Humboldt Co.: Pine 

Forest Range, 11 mi N of Leonard Creek 

Ranch, 1950 m, 27 Jun 1964, Holmgren & 

Reveal 1120 (RSA). New Mexico. San Miquel 

Co.: T. M. O’Connor Ranch, South 

Rim Pasture, 2100 m, 1.5 mi E of Las Vegas, 

28 Jul 1984, Hill 14631 (RSA); Valencia 

Co.: Mt. Taylor, San Mateo Mts., College 

experimental area, 20 mi E of Grants, 

2530 m, 4 Sep 1935, Parker 2333 (RSA). 

Wyoming. Crook Co.: Bear Lodge Range, 

Reuter Canyon, 5 mi N of Sundance, 1770 

m, 12 Jul 1960, Porter & Porter 8374 

(RSA). MEXICO. Baja California: Sierra, 

San Pedro Martir, Dead Horse Meadow, 

SW end of Venado Blanco, 17 Jul 1988, 

Boyd et al. 2628. (RSA). 

3b. Polygonum sawatchense subsp. oblivium. 

Canada. British Columbia: Road up 

to Windy Joe, Manning Park, 1470 m, 4 

Aug 1957, Beamish 7856 (GH). uNITED 

sTATES. california. Nevada Co.: Castle 

Peak, 31 Jul 1903, Heller s.n. (GH); Siskiyou 

Co.: Grass Lake, 18 Jul 1948, Mason 

13623 (RSA); Rocky summit, ridge road to 

Deadwood Lookout, mountains W of Yreka, 

25 Jun 1952, Ownbey & Preece, Jr. 

3345 (NY). Idaho. Elmore Co.: W side 

Lava Mt. at headwaters of Russell Gulch, 

Boise National Forest N of Smith Prairie, 

2290 m, 15 Jul 1981, Ertter & Grimes 4531 

(RSA). Nevada. Elko Co.: hillsides above 

Maggie Summit, Bull Run Mts., 2040 m, 

20 Jun 1980, Grimes et al. 1646 (NY); 

Humboldt Co.: Sonoma Range, Water Canyon, 

2070 m, 10 Jul 1964, Holmgren & Reveal 

1374 (NY). Oregon (County not given): 

Achoco Forest, 22 Jun 1932, Peck 

17068 (NY); Josephine Co.: summit of the 

Siskiyou Mts., 1370 m, 21 Jun 1922, Heller 

s.n. (NY); Lake Co.: Willow Creek Forestry 

Camp, Warner Mts., 1770 m, 24 Jun 1973, 

Munz 18361 (RSA). Washington. Asotin 

Co.: ridge leading N of Big Butte on the 

breaks of the Grand Ronde River, 1520 m, 

3 Jun 1939, Meyer 1622 (GH). 

4. Polygonum engelmannii. UNITED 

STATES. Colorado. Boulder Co.: near 

Boulder, 1520–1830 m, Jul 1902, Tweedy 

s.n. (NY); El Paso Co.: Manitou (Springs?), 

2100 m, 1 Aug 1901, Clements & Clements 

s.n. (DS); Pikes Peak, below Mountain 

View, 1 Aug 1943, Ewan 15145 (CAS). 

Idaho (County not given): Little Bear 

Creek, 13 Aug 1942, Degener & Peiler 

16834 (NY). Montana. Carbon Co.: Beartooth 

Mts., NW above bridge across Hell 

Roaring Creek, 2770 m, 12 Aug 1977, 

Lackschewitz 7826 (NY). Wyoming. Albany 

Co.: Jelm Mt., just below the summit, 

28 Aug 1977, Hartman & Hammel 4965 

(CAS); Morton’s Pass, NE of Bosler, 18 Jul 

1950, Ripley & Barneby s.n. (CAS); E of 

Laramie, 2190 m, 22 Jun 1943, Porter s.n. 

(NY); Lone Tree Pass, Laramie, 21 Jul 

1939, Brenckle & Mellete 39–02 (NY). 

5. Polygonum austiniae. UNITED 

STATES. California. Lassen Co.: Diamond 

Mts., Diamond Peak, 2350 m, 3 Jul 1989, 

Schoolcraft 1946 (UC). Idaho. Gooding 

Co.: N of Clover Creek Rd. between Hill 

City and Bliss, SW side of Davis Mt., in 

the Bennett Hills, 12 Jun 1981, Ertter 4190 

(NY). Oregon (County not given): near 

head of Dry Creek, 1650 m, 6 Jun 1896, 

Leiberg 2208 (NY); Harney Co.: 100 mi SE 

of Burns, S tributary to Alvord Creek, well 

up on the E side of Steens Mts., 2440 m, 

30 Jun 1959, Cronquist 8588 (NY); W 

slope of Steens Mts., 28 Jun 1942, Peck 

21454 (NY). Montana. Lewis and Clark 

Co.: off the Bear Creek Rd., meadow in the 

Bear Creek Canyon, 20 Jul 1982, Lackschewitz 

& Ramsden 10034 (NY). Nevada. 

Elko Co.: Rocky Mts., Jarbidge, 2130 m, 6 

Jul 1912, Nelson & Macbride s.n. (NY); 

Eureka Co.: Robert Creek Mts., ridge E of

26 BRITTONIA 

[VOL. 57 

Robert’s Creek, 4 Aug 1984, Tiehm & 

Nachlinger 9129 (NY); Humboldt Co.: N 

side of Hinkey summit, Martin Creek, 2190 

m, 28 Jun 1975, Williams & Tiehm 1212 

(NY). 

6. Polygonum minimum. CANADA. Alberta: 

Rocky Mts., Lake Louise, 7 Aug 

1919, Hunnevel 6305 (GH). United States. 

California. Fresno Co.: Hutchinson Meadow 

Area, 10 mi E of Florence, 3690–3810 

m, 21 Aug 1955, Quibell 5949 (GH); Inulare 

Co.: between East Lake and Reflection 

Lake, 5 Aug 1940, Howell s.n. (CAS); 

Mendocino Co.: Anthony Peak, 8 Aug 

1943, Howell 19195 (DS); Trinity Co.: N 

Yolla Bolly Mts., 20 Jul 1951, Munz 16734 

(DS); Tulare Co.: Kaweah Peaks, near Soda 

Spring, Big Arroya Soda Springs Trail, 28 

Jul 1987, Dudley s.n. (DS). Montana. Flathead 

Co.: Sperry Glacier, 1 Sep 1903, Umbach 

823 (GH). Nevada. Washoe Co.: 

Carson Range, Sierra Nevada, stream draining 

Ginny Lake, 27 Jul 1976, Tiehm 2596 

(CAS). Oregon. Marion Co.: Breitenbush, 

12 Jul 1935, Peck 18827 (CAS). Washington. 

Grays Harbor Co.: Bob Mt., 1250 and 

1400 m, 27 Jul 1934, Rossbach & Hodgdon 

s.n. (GH); Pierce Co.: Mount Rainier National 

Park, 16 Aug 1963, Hitchcock s.n. 

(DS). 

7. Polygonum nuttallii. CANADA. British 

Columbia: ca. 10 mi E of Bella Coola 

on road to Anahim Lake, 21 Aug 1956, 

Calder et al. 20322 (CAS); Chilliwack Valley, 

between 49� and 49�10�N, 121�25� and 

122�W, 9 Aug 1906, Spreadborough s.n. 

(NY). United States. Oregon. W Oregon, 

Aug 1880, Howell s.n. (CAS); Clackamas 

Co.: 60 mi E of Portland, near Bonneville 

Dam, mouth of Tanner Creek, 14 Aug 

1982, Neese et al. 12234 (NY); Columbia 

Co (?).: St. Helen, Oct 1882, Howell s.n. 

(CAS, NY). Washington: Mason Co.: Lake 

Cushman, gravel bar of Skokomish River, 

Aug 1895, Piper s.n. (NY); Skamania Co.: 

Cape Horn, 18 Aug 1894, Suksdorf 2288 

(NY) 

8. Polygonum spergulariiforme. CAN- 

ADA. British Columbia: Vancouver Island, 

Hats, Parksville, Sep 1915, Carter s.n. 

(CAS). United States. California. Del Norte 

Co.: Sasquet, 17 Sep 1912, Eastwood s.n. 

(CAS); Humboldt Co.: Bald Hills, Knee- 

land, 15 Sep 1930, Parks & Tracy 767 

(DS); Ireka Co.: 23 Oct 1922, Eastwood 

s.n. (CAS); Lassen Co.: Blacks Mt. Experimental 

Forest, 1800 m, 29 Jul 1964, Quick 

s.n. (CAS); Marin Co.: Dillons Beach, 6 

Sep 1947, Howell s.n. (CAS); Nevada Co.: 

Donner Lake, 1830 m, 10 Aug 1931, Peirson 

9564 (CAS); Shasta Co.: Clark Creek 

Rd., just W of Hwy. 89, 9 Jul 1986, Anderson 

3114 (CAS); Sierra Co.: road from 

Dog Valley Summit to Hobart Mills, turn 

to Verdi Peak, 1830 m, 29 Aug 1976, Williams 

76–106 (CAS); Siskiyou Co.: near 

Wagon Creek Falls, E side of Mt. Eddy, 

1370 m, 20 Jul 1916, Heller s.n. (CAS). 

Oregon. Curry Co.: Gold Beach, Nov 1915, 

Hoyt s.n. (DS); Josephine Co.: summit of 

Siskiyou Mts., 1370 m, 21 Jun 1922, Heller 

s.n. (DS). Washington. Skamania Co.: between 

Cooks and Hood, 14 Oct 1925, Suksdorf 

s.n. (DS). 

9. Polygonum majus. United States. Idaho. 

Adams Co.: 20 mi SE New Meadows, 

near Hwy. to Weiser, 24 Jun 1946, Hitchcock 

& Muhlick s.n. (DS); Canyon Co.: Big 

Willow, 28 May 1910, Macbride 133 (DS); 

Idaho Co.: 1.6 mi E of Slate Creek, 28 Jun 

1950, Jones 126 (DS); Nez Perces Co.: near 

Lewiston, 29 May 1896, Heller & Heller 

s.n. (DS). Oregon. Baker Co.: Roadside 

banks along Pine Creek, 11 Jun 1950, 

Cronquist 6550 (DS); Umatilla Co.: 11 mi 

E of Pendelton on road to Meacham, 21 Jun 

1935, Keck & Clausen 3599 (DS); Wallowa 

Co.: 5 mi NE of Elgin, 17 Jul 1946, Maguire 

& Holmgren s.n. (DS). Washington. 

Asotin Co.: 1 mi SE of Anatone, 18 Jun 

1949, Cronquist & Jones 5859 (DS); Klickitat 

Co.: 1.7 mi Dallesport, 13 Sep 1987, 

Halse 3522 (CAS); Lincoln Co.: 3 mi above 

Grand Coulee Dam, S side of Columbia 

River, 18 May 1940, Rogers 461 (CAS); 

Whitman Co.: Wawawai, 27 Jun 1933, 

Thompson 9242 (DS). 

10. Polygonum gabrielae. UNITED 

STATES. Oregon. Grant Co.: 7 mi S of Mt. 

Vernon, N-facing slopes, overlooking Laycock 

Creek, T14S, R30E, S26, 1370 m., 29 

Jun 1953, Cronquist 7330 (NY). 

11. Polygonum cascadense. United 

States. Oregon. Klamath Co.: 17 mi W of 

Crater Lake, 31 Jul 1916, Peck 6245 (GH); 

Crater Lake National Park, 1680 m, 17 Jul


27 

1936, ‘‘J.S.’’ 67 (UC). Lane Co.: Mouth, 

French Pete Creek, S Fork McKenzie, 1700 

m, 26 Jun 1967, Hickman 399–1 (UC); Rebel 

Rock, 30 Jun 1965, Hickman 145–2 

(JEPS); Linn Co.: Iron Mt., 1.5 mi N of 

Tombstone summit, 15 Aug 1957, Steward 

7336 (GH). 

12. Polygonum utahense. UNITED 

STATES. Utah. Garfield Co.: Escalante, 17 

Sep 1935, Cottam 6507 (CAS).

Taxonomy of the Polygonum douglasii (Polygonaceae ... - WLU

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