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 petricosa Dewey

Cyperaceae, Sedge family.

Published in Amer. J. Sci. 29: 246. 1836.

Type: Canada: "Summits of Rocky Mountains" [probably W of Jasper, Alberta], leg. Drummond 283. Holotype: GH.

Synonymy. Carex franklinii Boott in Hooker, Fl. Bor. Amer. ii. 217. 1840.

Carex franklinii var. nicholsonis Boivin, Naturaliste Canad. 75: 207. 1948.

Carex lepageana Raymond, Can. Field-Nat. 66: 101. 1952.

Vegetative morphology. Plants 15–35(–50) cm high (to 90 cm tall on continental North America); perennial herbs; caespitose; loosely tufted in several tufts. Only fibrous roots present. Roots pallid-brown, or red-brown. Ground level or underground stems horizontal; rhizomatous; elongate (slender). Ground level or underground stems scales present (along the horizontal stems). Aerial stems erect; not filiform (but slender, 0.6–1.1 mm in diameter). Leaves present; distributed along the stems; alternate; marcescent. Petioles absent. Sheaths present; persisting; not forming a conspicuous build-up at the base of the plant; greyish brown (pallid, cylindrical, 5–25(-35) mm long, mouth 0.9–1.5 mm wide); sheath collars absent. Ligules present. Leaves grass-like. Blades 5–140(–200) mm long, 1–3(–3.5) mm wide, somewhat curled (greyish green), linear, flat or revolute or folded (V-shaped in cross section), veins parallel. Blade adaxial surface scabrous (scaberulous). Blade margins scabrous.

Reproductive morphology. Plants monoecious. Flowering stems triangular in cross section (with rounded angles). Flowering stems about as high as the leaves (Victoria Island record), or conspicuously taller than the leaves (continental North America); with leaves. Leaf or reduced bract subtending the base of the inflorescence present; conspicuous and leaf-like; shorter than the apex of the inflorescence; 5–20 mm long; persistent; with sheath shorter than the blade (but conspicuously long). Inflorescences a raceme of spikes (spikes 5–30 mm long × 3–7 mm wide, the lower ones inclined or pendent); oblong, or ovate, or obovate (oblanceolate); 4–10(–15) cm long; 15–40 mm wide. Pedicels scabrous (scaberulous). Cladoprophylls present. Inflorescence multispicate. Inflorescence 3–5(–8) spikes (lateral spikes 5–30 mm long × 3–7 mm wide). Individual spike(s) ascending, or divergent. Terminal spike completely staminate, or staminate at the apex (sometimes with a second or third staminate or bisexual spike, 10–28 mm long × 1.8–4 mm wide; staminate scales brown or black with hyaline margins, oblong-ovate, 3.1–6.2 mm long × 1–3 mm wide). Floral scales shorter than the perigynium in fruit; brown (dark or blackish); with margins and sometimes midvein paler in colour than the adjacent area of the scale (sometimes shortly awned); ovate; 3.5–4.5(–5) mm long; 1.6–2 mm wide; glabrous; apex obtuse, or acute. Flowers unisexual. Staminate flowers conspicuous. Perianth represented by a perigynium. Stamens present (staminate flowers), or absent (pistillate flowers); 3. Anthers (1.5–)3–3.5 mm long. Ovary superior; carpels 3; syncarpous. Perigynia sessile. Styles 3; partially fused; slender, not extending beyond the beak, or slender, 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; broadly ovate, or elliptic; 5–6 mm long; 1.3–2 mm wide; erect or ascending; straw-coloured (at the base), or black, or brown (at the apex); membranous; surface dull; scabrous (ciliate-serrulate, particularly near the beak); faintly veined; with 2 keels; apices beaked with a short beak, or merely conical or rounded; apex oblique, becoming slightly bidentate. Fruit sessile; dry; an achene; indehiscent. Achenes trigonous; not filling the upper part of the perigynia. Seeds 1.

Chromosome information. 2n = 47–48.

2n = 47–48. Is a chromosome count for Carex petricosa Dewey var. misandroides (Fernald) B. Boivin by Gervais et al. (1999, Eastern Canada).

Ecology and habitat. Substrates: slopes; dry; rocks; with low organic content; calcareous.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories. Range in the Canadian Arctic Archipelago limited. Rare. Low Arctic. Arctic islands: Victoria (near Walker Bay and Minto Inlet).

Northern hemisphere distribution. Amphi-Beringian (slightly), or Cordilleran (with a gap between Alaska-Yukon and southern Alberta). East Chukotka, West Alaska, North Alaska – Yukon, Central Canada.

General notes. Ball and Zoladz (1994) studied the taxonomy of C. petricosa and related species in North America, C. franklinii, and C. misandroides. In a morphological study of herbarium specimens, the multivariate analyses they used failed to adequately differentiate the taxa and led to the conclusion that all should be treated as a single species. The western and eastern populations differed in the proportion of flowers that were distigmatic. Western plants were mostly tristigmatic or had not more than 50% distigmatic flowers. Eastern plants were mostly distigmatic or had more than 50% distigmatic flowers. Consequently, two varieties were recognised in C. petricosa, var. petricosa from the west and var. misandroides (Fernald) B. Boivin from the east (Newfoundland, Quebec, but not in the Arctic islands). Elven et al. (2003) also recognised two varieties.

Egorova (1999) accepted Carex franklinii as a species (in a list of non-Russian species of the section), as did Hultén (1968), Porsild and Cody (1980), and Cody (1996).

Ball commented that Carex franklinii Boott, often considered as a separate species (e.g., by Hultén 1968a, Porsild and Cody 1980, and Cody 1996), is a synonym of C. petricosa Dewey s.s. Carex petricosa seems to represent small high-altitude plants, whereas C. franklinii seems to represent larger plants from a lower altitude. There is ample material collected from the type area (Alberta), which illustrates the full range of variation.

Ball and Mastrogiuseppe (2002) distinguished varieties in this taxon with the following key (p. 478):

"Stigmas 3; achenes trigonous in at least half of the pistillate flowers and fruits... C. petricosa var. petricosa

Stigmas 2; achenes biconvex in at least half of the pistillate flowers and fruits...C. petricosa var. misandroides".

The record from the Canadian Arctic Archipelago is assigned to C. petricosa var. petricosa. The distribution of C. petricosa var. misandroides is limestone barrens and shores, in Newfoundland Labrador and Quebec.

Illustrations. • Herbarium specimen. Plants with rhizomes, somewhat curled leaves, and multispicate inflorescences. Nunavut, Victoria Island. CAN 127571. • Close-up of inflorescence. Close-up of a lateral spike with staminate flowers at the apex and pistillate flowers below. CAN 127571. • Type specimen. Type specimen of Carex franklinii Boott var. nicholsonis Boivin, Nat. Canad. 75: 207. 1948. N.W.T., Nicholson Island, Arctic Coast. 13–14 August, 1927. A.E. and R.T. Porsild 2840. CAN 22969. • 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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