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

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.
Distribution and ecology. Canada (Alberta,
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-