Monographs Details: Luzula rufescens Fisch. ex E.Mey.
Authority: Ebinger, John E. 1964. Taxonomy of the Subgenus Pterodes, Genus Luzula. Mem. New York Bot. Gard. 10 (5): 279-304.
Family:Juncaceae
Description:Species Description - Perennial, short stolons to caespitose, stolons to 4 cm long, less than 1 mm wide, having dark brown scale-like leaves and slender adventitious roots; basal leaves with flat blades, 1-3 mm wide, to 6 (rarely 10) cm long, margins sparsely pubescent, apex callose-tipped; culms erect, slender, smooth, 10-20 (rarely 30) cm tall, bearing 2-3 leaves; sheaths closed, lightly pubescent at the throat with white hairs; blades linear, flat, 1-2.5 mm wide to 4 (rarely 6) cm long, tapering gradually to the tip, margins glabrous to sparsely pubescent, usually curled toward the apex, callose-tipped; inflorescence terminal, simple, rarely a few secondary pedicels are present; pedicels spreading to slightly nodding, never reflexed; basal bract erect, much shorter than the inflorescence, leaf-like, green, margins glabrous to slightly pubescent, callose-tipped; other bracts brown with hyaline margins, short, the inner bract at the base of each pedicel, brown, truncate with a hyaline tip, usually glabrous; outer bract usually shorter than the inner, tip acuminate, usually glabrous; bracteoles at the base of the flower ovate, hyaline to light brown, half as long as the flower; perianth segments similar, equal, lanceolate, entire, light or dark brown with hyaline margins, 1.6-2.5 mm long; stamens 6 shorter than the perianth, filaments linear, the same length as the anthers, anthers linear; pistil erect, ovary acute at the tip, 3 angled, style filiform less than 0.7 mm long, stigmas 3 erect to spreading 1.5 mm long equalling to slightly longer than the perianth; fruits equalling to exceeding the perianth, to 3.5 mm long, tip acute to subtruncate with a short mueronate tip from the persistent base of the style, stramineous to light brown, sometimes flecked with purple; seeds 1.4 mm long, dark brown to black; caruncle erect to slightly curved, narrow, to 0.6 (rarely 1.0) mm long.

Discussion:

Luzula rufescens Fisch. ex E. Mey. Linnaea 22: 385. 1849.

Juncodes rufescens (Fisch. ex E. Mey.) O. Ktze. Eev. Gen. PI. 2: 725. 1891.

Luzula rufescens Fisch. ex E. Mey. var. macrocarpa Buchenau, Das Pflanzenreich 25(4) : 47. 1906.

Luzula macrocarpa (Buchenau) Nakai, Eep. Veg. Quelpaert 30. 1914.

Luzula plumosa Wall, ex E. Mey. var. macrocarpa (Buchenau) Ohwi, Fl. Japan 271. 1953.

Type. Turczaninow, in Siberia near Irectia. A specimen in the herbarium of the Department of Systematics and Plant Geography, Botanical Institute, Academy of Science, USSR. (LE) is labeled Luzula rufescens, and was originally from the Fischer Herbarium. This specimen was collected by Turczaninow in Irectia in 1828 and probably represents the type of this species.

Hybrids. No naturally occurring hybrids have been reported. Moreover, in the material examined no intermediate plants were found between this species and Luzula rostrata var. jimboi in northeastern Siberia. The similarity of these two species, however, indicates that hybrids would probably occur if the two species come into contact. Also, it is very probable that L. rufescens hybridizes with L. plumosa in southeastern Siberia. Unfortunately there is very little herbarium material from this region, so no conclusive results could be obtained.

Luzula rufescens is easily distinguished from the other members of the subgenus by the smaller flowers, narrower leaves, and usually simple corymbose inflorescence with erect to spreading pedicels. However, occasionally it has been confused with L. plumosa var. brevipes and L. rostrata. The relationship of this species to others of the subgenus is still undetermined because, in the experiments of Nordenskiold (1957) the Fi hybrids were usually sterile. However, the small flowers, stoloniferous habit and slightly curved caruncle indicate a relationship to L. rostrata.

The nomenclature of this species is very simple. One variety (macrocarpa) has been described, but present information indicates that this is just natural variation within the species. This varietal name has also been raised to specific rank [L. macrocarpa (Buchenau) Nakai], and moreover has been considered a variety of another species (L. plumosa var. macrocarpa). This latter transfer was used for the Japanese species of L. plumosa. The type specimen of this name was examined, and in the author's opinion it is referable to L. rufescens rather than L. plumosa.

This species is found on two continents. In Asia it occurs from the tundra region of eastern Siberia, south into the mountains of Mongolia and northern China, while in North America it is found in Alaska and the western part of the Yukon District of Canada (Fig. 9). Throughout this range it is polymorphic. Most of the specimens from northeastern Siberia are less than 20 cm tall and the mature capsule equals to slightly exceeds the perianth, while the southern specimens are usually taller (to 30 cm) and the capsule exceeds the perianth. These taller plants have generally been referred to as variety macrocarpa. In contrast, the plants from North America range in size from 20-30 cm tall, the mature capsule exceeds the perianth and is flecked with purple. Varieties could not be distinguished, however, because of the high variability of the traits mentioned above.