This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Gabrous, similar to small forms of C. stricta, culms slender, rough above, seldom over 2° high. Leaves 1"-1 1/2" wide, rough-margined, shorter than or sometimes a little overtopping the culm, the lower sheaths slightly or not at all filamentose; lower bract foliaceous, about equalling the culm; pistillate spikes linear-cylin-dric, 6"-15" long, about 2" in diameter, erect or somewhat spreading, all sessile or nearly so, sometimes with a few staminate flowers at the summit; perigynia sub-orbicular or obovate, obtuse, about 3/4" broad, faintly 2-4-nerved, minutely beaked, the orifice entire; scales lanceolate, purplish, spreading, very acute, strongly exceeding the perigynia; stigmas 2.
Glabrous, rather light green, in rather loose clumps, culms thick at base, aphyllopodic, erect, smooth or slightly scabrous above, 1 1/2°-3° tall, from thick hard rootstocks, short-stoloniferous. Leaves about 2" wide, those of the fertile culm very short; sheaths not filamentose; lower bract leaf-like, sheath-less or short-sheathing; staminate spike usually one, stalked; pistillate spikes 3-6, erect, spreading or drooping, slender-peduncled or upper often sessile, linear, 1'-3' long, about 2" in diameter, sometimes compound, often loosely flowered toward the base; perigynia oblong or narrowly ovate, green, nerveless, l"-1 1/2" long, the short beak more or less twisted when dried; scales ovate-oblong, obtuse or subacute, dark with a green midvein, shorter and mostly narrower than the perigynia; stigmas 2.
Generally in rocky beds of streams, Quebec to Minnesota, south to North Carolina and Missouri. Ascends to 2600 ft. in Virginia. June-July.
Carex rigida Gooden. Trans. Linn. Soc. 2: 193. pl. 22.
1824. Carex hyperborea Drej. Rev. Crit. Car. 43. 1841.
Glabrous and smooth throughout or very nearly so, culms phyllopodic, usually low and rigid, in small clumps, sharp-angled, erect, 4'-18' tall, freely short-stoloniferous, the rootstocks stout, scaly. Leaves 1 1/2"-3 1/2" wide, with revolute margins, not exceeding the culm, the lower bracts similar, but shorter; staminate spike stalked, sometimes pistillate at the base; pistillate spikes 1-4, short-oblong to linear-cylindric, usually loosely flowered at the base, dense above, 3"-2o" long, 1 1/2'-2 1/2" thick, the upper sessile, the lower often slender-stalked; perigynia oval, 1 1 /4"-ii" long, ascending, faintly nerved or nerveless, scarcely beaked, the orifice entire; scales purple-brown with a narrow light midvein and often with hyaline margins, obtuse or the lower acutish, equalling or a little exceeding the perigynia; stigmas 2, rarely 3.
Greenland to Alaska, south to the higher mountains of northern New England and New York, Colorado and California. Also in Europe and Asia. Very variable. Summer.