Flora of North America species comparison

Calamagrostis stricta grows throughout northern North America; it also is found in Europe and northeastern Asia. It grows in habitats ranging from meadows and grassland to wetlands, sandy shorelines, and sand dunes, from sea level to 3400 m. Primarily a species of open settings, it is frequently found in association with shrubs. Both subspecies have a notable but not exclusive association with alkaline to saline substrates.

Calamagrostis stricta comprises both sexual and apomictic populations. Two subspecies, C. stricta subsp. stricta and subsp. inexpansa, intergrade but generally differ as described below. Greene (1984) treated subsp. inexpansa as consisting of the apomictic plants, probably derived from the sexual subsp. stricta. A number of apomictic variants were previously recognized at the species level; among these were C. lacustris (Kearney) Nash and C. fernaldii Louis-Marie, which are morphologically nearly indistinguishable from each other (Greene 1980, 1984).

Plants of short stature and short inflorescences, growing in the north, have been referred to as Calamagrostis stricta subsp. borealis (C. Laest.) Á. Löve & D. Love or C. stricta var. borealis (C. Laest.) Hartm. These intergrade with taller plants; they are not recognized here as a distinct taxonomic entity.

Calamagrostis stricta is sometimes confused with C. lapponica (see previous). In addition to the differences noted in the descriptions and key, the glumes of C. stricta are not as smooth and glossy, and are generally brown at the tip; those of C. lapponica are typically purple.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Calamagrostis purpurascens grows in alpine tundra, on subalpine slopes, in grasslands, sand dunes, meadows, coniferous and deciduous forests, and disturbed soils, usually on rocky ridgetops and slopes and, infrequently, on valley floors. It prefers well- to moderately-drained, medium- to coarse-textured substrates, including scree and talus, that are often calcareous, at elevations from 15-4000 m. Its range extends from Alaska through Canada to Greenland and Newfoundland, including the islands of the Canadian arctic, and south in the western mountains to California and northern New Mexico. It does not occur near the open coast except in the Aleutian Islands, the Arctic, and the Olympic Peninsula in Washington. In Asia, it ranges from eastern and central arctic Siberia south to the Kamchatka Peninsula and Sakhalin Island.

The hairy adaxial leaf surfaces are a reliable diagnostic characteristic for Calamagrostis purpurascens. Many specimens from Washington and Oregon currently identified as C. purpurascens belong to C. tacomensis (p. 716). In addition to differing in its leaf vestiture, C. purpurascens has shorter awns and panicle branches, and more scabrous glumes, than C. tacomensis. Plants of C. purpurascens that have short awns barely projecting beyond the lemma margins have been mistaken for C. montanensis (p. 724), but that species does not have hairy adaxial leaf surfaces.

Calamagrostis purpurascens var. laricina Louis-Marie supposedly has shorter glumes and awns, with the awns barely exserted, if at all. The variety is not recognized here because the range in variation in these two characters is continuous; plants that match the description of var. laricina are widely distributed throughout the range of the species. Some collections having both short and long awns are on the same sheet.

Calamagrostis lepageana Louis-Marie, collected only from Mont-Commis, Quebec, is here included within C. purpurascens. It differs from the typical form in that the panicle is more open; the branches are sparsely short-scabrous; and the glumes are at the shortest limit for the species, and are smooth or sparsely scabrous only on the keels. Other characteristics, including the densely hairy adaxial leaf surfaces, fit C. purpurascens.

According to Norwegian botanist Reidar Elven (pers. comm.), five specimens at ALA, collected from four sites on the Seward Peninsula in Alaska, are distinct from Calamagrostis purpurascens but are related to it, or are possibly a hybrid between C. purpurascens and C. sesquiflora (p. 714). They differ from typical C. purpurascens in having bristly (versus hairy) upper leaf surfaces, and acuminate, dark purple (versus acute, pale pink or lilac) glumes. They can be called C. purpurascens subsp. arctica (Vasey) Hulten; in eastern Russia this taxon is recognized at the species level as C. arctica Vasey.

(Discussion copyrighted by Flora of North America; reprinted with permission.)