Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Carex williamsii Britton

English: Williams' sedge,

French: Carex de Williams,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Cyperaceae, Sedge family.

Published in Bull. N.Y. Bot. Gard. 2: 159. 1901.

Type: Canada: Yukon Territory, Dawson, 12.06.1899, leg. R.S. Williams. Holotype: NY.

Synonymy. Carex capillaris L. var. williamsii (Britton) B. Boivin, Natural. Can. 94: 522. 1967.

Carex novograblenovii Kom., Byull. Bot. Sada SSSR 30, 1–2: 199. 1932.

Vegetative morphology. Plants 5–15 cm high (Arctic islands, to 30 cm high on continental North America); perennial herbs; caespitose. Only fibrous roots present. Ground level or underground stems absent. Aerial stems decumbent (slightly); filiform (0.3–0.5 mm in diameter). Leaves distributed along the stems; alternate; dying annually and non-persistent. Petioles absent. Sheaths present; breaking down into fibres; not forming a conspicuous build-up at the base of the plant; greyish brown; sheath collars absent. Ligules present. Leaves grass-like. Blades 20–60 mm long, 0.4–0.7 mm wide (filiform), straight, linear, channelled, veins parallel. Blade adaxial surface glabrous. Blade margins scabrous (or scaberulous, young leaves and towards the leaf apices).

Reproductive morphology. Plants monoecious. Flowering stems circular or oval in cross section. Flowering stems conspicuously taller than the leaves; with leaves. Leaf or reduced bract subtending the base of the inflorescence present; reduced, or scale-like; shorter than the apex of the inflorescence; 5–15 mm long; persistent; with sheath shorter than the blade. Inflorescences a raceme of spikes; 1–1.5 cm long; 2–4 mm wide. Pedicels glabrous. Cladoprophylls present. Inflorescence multispicate. Inflorescence 2–5 spikes (lateral spikes with 3–10 flowers, 4–10 mm long × 2–2.5 mm wide). Individual spike(s) ascending (and widely spaced on a zigzag rachis). Terminal spike completely staminate, or staminate at the apex (staminate scales brown with hyaline margins and paler midveins, oblong-lanceolate, 2.5–3 mm long, about 0.8 mm wide, apex obtuse or mucronate). Floral scales shorter than the perigynium in fruit; orange-brown, or green; with margins and sometimes midvein paler in colour than the adjacent area of the scale; ovate; falling early; 1–2.5 mm long; 1–1.4 mm wide; glabrous; apex obtuse. Flowers unisexual. Staminate flowers inconspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers 1–1.2 mm long. Ovary superior; carpels 3; syncarpous. Perigynia contracted at the base into a stipe (that is short). Styles 3; partially fused; slender, not extending beyond the beak. Stigmas per ovary 3. Placentation basal. Ovules per ovary 1. Fruit surrounded by a perigynium. Perigynia fused to the apex except for a small aperture through which the style protrudes; lanceolate, or elliptic; 2.5–3.2 mm long; 0.9–1.2 mm wide; spreading at maturity; golden brown; membranous; surface dull (or slightly glossy); glabrous; strongly veined; with 3 keels; apices beaked with a long beak (the tapering apex of the perigynia, 0.7–1 mm long); apex not bidentate or oblique. Fruit sessile; dry; an achene; obovate; indehiscent. Achenes trigonous; not filling the upper part of the perigynia. Seeds 1; 1.2–1.7 mm long (about 0.7 mm wide).

Chromosome information. 2n = 18 and 46.

2n = 18. Löve et al. (1957, Alaska, without further information); Löve (1981d, central Canada);

2n = 46. Yurtsev and Zhukova (1978, eastern Chukotka); Zhukova and Petrovsky (1980, western Chukotka; 1981a, northeastern Asia); Zhukova (1980, southern Chukotka).

The discrepancy between the low-ploidy chromosome count of Löve et al. (1957) and Löve (1981d) and the higher-ploidy ones of the Russians is strange and indicates that the counts were made on different taxa. The Russian identification of the taxon is reliable with vouchers at LE that have been checked.

Ecology and habitat. Substrates: wet meadows, hummocks, seashores; imperfectly drained moist areas (in one site, described as "dripping wet"); sand, moss. Found in grassy wet meadows with Eriophorum angustifolium and Carex membranacea. Polunin (1940) recorded this species as very occasional in rather dry grassy areas within its limited range, and also observed that it is "never noted as common even locally, or of any importance whatsoever; nevertheless a charming little sedge.".

North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Rare. Low Arctic. Arctic islands: Baffin (Iqaluit and Ogac Lake), Victoria, Southampton (literature record).

Northern hemisphere distribution. North American, or Siberian. Polar Ural – Novaya Zemlya, Yamal–Gydan, Kharaulakh, West Chukotka, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay.

General notes. This species was mentioned in Porsild (1957) as similar to C. capillaris and occurring from Alaska to Labrador. Porsild and Cody (1980) mapped records from southern Baffin Island. Four collections from Baffin Island, Iqaluit, have been made since Porsild (1957). It occurs in the tundra of Hudson Bay coast and in the field may be mistaken for C. krausei.

Peter Ball (personal communication, Nov. 2004) noted that in the material he had seen this species is often staminate and only sometimes androgynous. He questioned whether these are really androgynous spikes or whether they are a staminate terminal spike with the distal lateral spike reduced to a single perigynium. Occasionally, there is more than one perigynium. He noted also that C. williamsii is unlike C. capillaris s.l. in which plants with gynecandrous spikes show up erratically in the Rockies in Alberta, and in Greenland sometimes you get staminate and gynecandrous spikes on the same collection and less often on the same plant. Gynecandrous spikes are very uncommon in Canada, but they seem quite common in Greenland.

Illustrations. • Close-up of plant. Plants about 15 cm high, relatively large for this delicate species. Nunavut, Baffin Island, Ogac Lake. CAN 302045. • Close-up of multispicate inflorescence. Inflorescence of 3–4 widely spaced spikes. Terminal spike male (note anther) at the apex and with a single female flower (note perigynium) at the base. This is in contrast to Carex capillaris and Carex krausei where the terminal spike may be female at the apex. Note floral scales shorter than the perigynium, midvein paler than the body of the scale, and perigynia spreading at maturity, apices tapering to a long beak. Nunavut, Baffin Island, Iqaluit. Sylvia Grinnell Park, north trail from parking lot. CAN 549904. • Mature perigynia. Note floral scales shorter than the mature perigynia, the prominent mid-rib on the scales, and the long beak on the perigynium. Nunavut, Baffin Island, Kimmirut. CAN 22425. • Arctic Island Distribution.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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