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

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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. Phenology. Flowering June–August. 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 wax pattern of type 2, with a narrow 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-
2005] COSTEA & TARDIF: POLYGONUM DOUGLASII COMPLEX 17 ditionally, the three species have perianth lobes with a different pattern of organization of epicuticular waxes (Figs. 4B; 5A, C). Distribution and ecology. Canada (Alberta, 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 almost 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). Distribution and ecology. Western 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. Phenology. Flowering June–September. 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). Annual herbs. Stems 2–30 cm long, 4angled, 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-
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Taxonomy of the Polygonum douglasii (Polygonaceae ... - WLU

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