Carex chordorrhiza Ehrh. ex L.f.
Suppl., p. 414. 1781.
Nomenclatural section used by Flora of North America project subgenus Vignea, sect. Chordorrhizae (Fries) Mackenzie
Plants with single unbranched stems; less than 15 cm high, or more than 15 cm high; 7–20(–25) cm high. Roots pallid-brown. Ground level or underground 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; simple. Sheaths green. Ligules present. Blades straight; linear; folded; glabrous. Blades adaxial surface glabrous.
Flowering stems about as high as the leaves, or conspicuously taller than the leaves. 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; 0.2–1 cm long; with sheath shorter than the blade. 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 mid-vein paler in colour than the adjacent area of the scale; not reflexed (spreading to 90° at maturity); lanceolate; not falling early; 2.5–3.2(–3.5) mm long; 1.4–2 mm wide; glabrous. Perianth absent. Anthers 2–2.5 mm long. Styles slender, not extending beyond the beak. Stigmas per style 2. 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; surface glossy; glabrous; strongly nerved; apices beaked with a short beak. Achenes filling the perigynia; lenticular.
Chromosome information. 2n = 60 and 66.
Distribution. Circumpolar. Low arctic. Range in the Canadian Arctic Archipelago limited. Uncommon. Arctic Islands: Baffin (Iqaluit, Kimmirut), Victoria (Cambridge Bay and Tahoe Lake).
Ecology and habitat. Substrate around the margins of ponds, along streams, tundra, sea shore (on beaches); aquatic, or imperfectly drained; sand, silt; with low organic content, or with high organic content. Occasional to rare in wet tundra (Porsild, 1957), but can be 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 found 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: 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).
