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.

"shortened" is not a number.

... more about "Carex williamsii"
0.12 cm1.2 mm <br />0.0012 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
mucronate;obtuse;obtuse +
Peter W. Ball +
Britton +
rounded +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
v--shaped +
0 cm0 mm <br />0 m <br /> (2 cm20 mm <br />0.02 m <br />) +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
scale-like +  and leaflike +
parallel +  and divergent +
terete +, rolled +  and plicate +
Carex de Williams +
stipitate +  and 2-10-veined +
trigonous +, lanceolate +  and narrowly ovate +
round +  and trigonous +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Man. +, Nfld. and Labr. +, N.W.T. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +  and n Asia +
0–500 m +
open +, pistillate +  and staminate +
hypogynous +  and subtending +
biconvex +  and trigonous +
Fens, sedge meadows, moist tundra +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
basal +  and cauline +
with 1 or 2basal setae +  and entire +
subentire +  and entire +
with (1-)3-6(-30) bristles and/or scales +
not speckled redbrown +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.31 cm3.1 mm <br />0.0031 m <br />) +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Fruiting summer. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
long-sheathing +  and leaflike +
Bull. New York Bot. Gard. +
adventitious +
staminate +  and pistillate +
brown +  and pale-brown +
basal +  and proximal +
oblong-lanceolate;ovate +
0.8 cm8 mm <br />0.008 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
cylindric +
Illustrated +
1 +  and 3 +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
deciduous +
2-3(-4)-fid +
Carex sect. Capillares +
Carex williamsii +
Carex sect. Chlorostachyae +
species +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
plant +  and cespitose +