Carex chordorrhiza Ehrh.
Cyperaceae, sedge family.
Suppl., p. 414. 1782.
Nomenclatural section used by Flora of North America project subgenus Vignea, sect. Chordorrhizae (Fries) Mackenzie
Type: 77. Chordorrhiza. Carex chordorrhiza L. Upsaliae (UPS) holotype
Vegetative morphology. Plants perennial herbs; 7–20(–25) cm high; tufted with widely trailing ascending stems. Roots pallid-brown. Ground-level or under-ground stems horizontal; stoloniferous (to 1 m long); elongate. Scales present (sometimes leaf-like along the stolons). Aerial stems erect; not filiform (0.8–1.5 mm in diameter); triangular in cross-section; glabrous. Leaves distributed along the stems. Petioles absent. Sheaths persisting; not forming a conspicuous build up at the base of the plant; green; collars absent. Ligules present; membranous. Blades 20–100 mm long; 0.5–2.5 mm wide. Blades straight; linear; folded; veins parallel. Blades adaxial surface glabrous. Blades abaxial surface glabrous. Blade margins scabrous (scaberulous at the tip).
Reproductive morphology. Plants monoecious. Flowering stems present. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; with leaves; glabrous. Leaf or reduced bract closely associated with the base of the inflorescence present (easily overlooked); reduced, or scale-like; shorter than the apex of the inflorescence; 2–10 mm long; with sheath shorter than the blade; persistent (but withering early). Inflorescence spicate; 0.8–1.2 cm long; 2–8 mm wide; a single spike; lateral spikes sessile. Individual spike(s) erect. Terminal spike staminate at the apex (3–8 staminate flowers). Cladoprophyll absent. Staminate flowers inconspicuous. Floral scales shorter than the perigynium in fruit; orange brown; with margins, and sometimes midvein paler in colour than the adjacent area of the scale; not reflexed (spreading to 90° at maturity); lanceolate; 2.5–3.2(–3.5) mm long; 1.4–2 mm wide; glabrous. Perianth absent. Flowers unisexual. Stamens 3. Anthers 2–2.5 mm long. Carpels syncarpous. Styles slender, not extending beyond the beak. Stigmas per style 2. Placentation basal. Fruit surrounded by a perigynium. Perigynia with a slit running down the beak on the abaxial side through which the style protrudes; broadly ovate; 2.8–3.2 mm long; 1.3–1.7 mm wide; sessile (or with a very short stipe-like base); spreading at maturity; brown, or green; membranous (relatively thick); surface glossy; glabrous; strongly nerved; apices beaked with a short beak. Fruit an achene. Achenes filling the perigynia; lenticular.
Chromosome information. 2n = 60–70. 60–70. - Löve and Löve (1956b Iceland, 2n = 60, 1965a, 2n = c.60, 1981c central Canada, 2n = 62); Löve and Ritchie (1966 northern Canada, 2n = c.60); Knaben and Engelskjøn (1967 Norway, 2n = c.66); Zhukova and Petrovsky (1976 western Chukotka, 2n = 70); Zhukova et al. (1977a north eastern Asia, 2n = 70).
Distribution. Northern hemisphere distribution: circumpolar. Yukon, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Low arctic. Range in the Canadian Arctic Archipelago limited. Uncommon. Arctic Islands: Baffin (Iqaluit, Kimmirut), Victoria (Cambridge Bay and Tahoe Lake).
Ecology and habitat. Substrates: around the margins of ponds, along streams, tundra, seashores (on beaches); aquatic, or imperfectly drained moist areas; sand, silt; with low organic content, or with high organic content. Habitats: Occasional to rare in wet sedge marshy tundra (Porsild, 1957), but sometimes a dominant by pond margins, where it can be found with Hippurus vulgaris and Ranunculus pallasii. It can also act as a sand binder on beaches.
Notes. Polunin (1940) considered the characteristic habitat of this sedge to be the margins of freshwater pools in sheltered lowland areas, where it creeps with conspicuous long stolons on the surface of the wet mud from which the frequent culms arise. Polunin had observed many of the stolon extending out into the water, sometimes for nearly a metre, but in such cases they were barren. Susan Aiken collected this species growing in a wetland area behind the Nunavut Research Lab. (Iqaluit) in 1986 but was not able to find this Carex in 1998 after the area was partially drained.
Illustrations. • Herbarium specimen. Plants with conspicuously long rhizomes, sometimes as much as 1 metre long, CAN 26825. • Close-up of inflorescence. Unispicate inflorescences with staminate flowers at the top of the spike. CAN 26825. • Arctic Island distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
