Carex petricosa Dew.
Nomenclatural section used by Flora of North America project subgenus Carex, sect. Aulocystis Dumortier
Carex franklinii Boott
Carex distichflora Boivin
Carex magnursina Raymond
Carex lepageana Raymond
Carex macrogyna Turcz. ex Steud.
Carex petricosa var. distichiflora (Boivin) Boivin
Carex franklinii Boott var. nicholosonii Boivin
Plants not caespitose (but loosely clustered). Plants more than 15 cm high; 15–35(–50) cm high. Roots pallid-brown, or red-brown. Ground level or underground stems horizontal; rhizomatous; elongate. Scales present (along the horizontal stems). Aerial stems decumbent; not filiform (but slender, 0.6–1.1 mm in diameter); triangular in cross section (with rounded angles); glabrous. Leaves distributed along the stems. Sheaths greyish brown (pallid). Ligules present. Blades somewhat curled (grayish green); linear; flat, or revolute, or folded; scabrous (scaberulous, especially on the margins).
Flowering stems about as high as the leaves (Victoria Island record), or conspicuously taller than the leaves (Continental North America). Leaf or reduced bract closely associated with the base of the inflorescence present; conspicuous and leaf-like; shorter than the apex of the inflorescence; 3–8 cm long; with sheath shorter than the blade (but conspicuously long). Inflorescence spicate; oblong, or ovate, or obovate (oblanceolate); 4–10(–15) cm long; 15–40 mm wide. Pedicels scabrous (scaberulous). Inflorescence multispicate; 3–5 spikes; lateral spikes borne on pedicels (the lowermost spike usually remote). Individual spike(s) ascending, or divergent. Terminal spike wholly staminate, or staminate at the apex (sometimes with a second or third staminate or bisexual spike). Cladoprophyll present at the base of the peduncle of lateral spikes. Staminate flowers conspicuous. Floral scales shorter than the perigynium in fruit; brown; with margins, and sometimes mid-vein paler in colour than the adjacent area of the scale; obtuse, or acute; ovate; 3.5–4.5(–5) mm long; 1.6–2 mm wide; glabrous. Perianth absent. Anthers 3–3.5 mm long. Styles slender, not extending beyond the beak, or slender, extending beyond the beak. Stigmas per style 3 (or rarely 2). 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; sessile; erect or ascending; brown; surface dull; scabrous (particularly near the beak); faintly nerved; with 2 keels; apices beaked with a long beak; apex oblique, becoming slightly bidentate. Achenes not filling the upper part of the perigynia; trigonous.
Chromosome information. 2n = unknown?.
Distribution. North American (endemic in Northern Cordillera). Low arctic. Range in the Canadian Arctic Archipelago limited. Rare. Arctic Islands: Victoria (near Walker Bay).
Ecology and habitat. Substrate slopes; dry; calcareous; rock; with low organic content.
Notes. Ball and Zoladz (1994) studied the taxonomy of C. petricosa and related species in North America, C. petricosa, C. franklinii, and C. misandroides. In a morphological study of herbarium specimens the multivariate analyses they used completely failed to satisfactorily differentiate the taxa and lead 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 recognized in C. petricosa, var. petricosa from the west and var. misandroides (Fernald) Boivin from the east (Newfoundland, Quebec, but not in the Arctic Islands).
Illustrations. • Herbarium specimen. Plants with rhizomes, somewhat curled leaves, and multispicate inflorescences. Single record from 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. nicholosonii Boivin, Nat. Canad. 75.207. 1948. N.W.T., Arctic Coast, Nicholson Island, A.E. and R.T. Porsild, 2840, 13–14 Aug. 1927 CAN 22969. • Arctic Island distribution.
Cite this publication as: Aiken, S.G., Boles, R.L., and Dallwitz, M.J. 1999 onwards. ‘Cyperaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 6th November 2000. http://http://www.mun.ca/biology/delta/arcticf/. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
