Carex williamsii

Britton

Bull. New York Bot. Gard. 2: 159. 1901.

Common names: Carex de Williams
Illustrated
Treatment appears in FNA Volume 23. Treatment on page 475. Mentioned on page 473, 476.

Culms to 15(–30) cm. Leaf blades filiform, channelled, 2–8 cm × 0.25–1 mm. Terminal spike androgynous or staminate, ± level with lateral spikes, 2–8 × 0.6–1 mm. Lateral spikes 2–5, usually suberect, 3–10-flowered, 4–10 × 2–2.5 mm. Pistillate scales pale brown with hyaline margins and paler midvein, ovate, 1.8–2.2 × 1–1.4 mm, apex obtuse. Staminate scales brown with hyaline margins and paler midvein, oblong-lanceolate, 2.5–3 × 0.8 mm, apex obtuse or mucronate. Perigynia distinctly veined, lanceolate, 2.3–3.1 × 0.7–1 mm; beak 0.5–1 mm, margins entire or with 1 or 2 basal setae. Achenes obovoid, 1.2–1.5 × 0.7 mm.


Phenology: Fruiting summer.
Habitat: Fens, sedge meadows, moist tundra
Elevation: 0–500 m

Distribution

V23 872-distribution-map.jpg

Man., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Yukon, Alaska, n Asia.

Discussion

Á. Löve et al. (1957) reported a chromosome number of 2n = 18 for a North American plant of Carex williamsii; that number has not been confirmed. T. V. Egorova (1999) reported 2n = 46 for Asian plants of C. williamsii, which is within the range of chromosome counts reported for other species in sect. Chlorostachyae. It is not clear whether the terminal spike of C. williamsii is consistently androgynous or whether it can also be staminate. Androgynous spikes have only 1–3 perigynia that are usually hidden by the lateral spikes.

Selected References

None.

Lower Taxa

None.
... more about "Carex williamsii"
Peter W. Ball +
Britton +
Carex de Williams +
Man. +, Nfld. and Labr. +, N.W.T. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +  and n Asia. +
0–500 m +
Fens, sedge meadows, moist tundra +
Fruiting summer. +
Bull. New York Bot. Gard. +
Illustrated +
Carex sect. Capillares +
Carex williamsii +
Carex sect. Chlorostachyae +
species +