Deschampsia cespitosa
Deschampsia cespitosa subsp. beringensis
tuft hair grass
Beringian hairgrass, tuft hair grass
(7) 35-150 cm, erect, not rooting at the lower nodes.
(15)70-140 cm.
mostly basal, sometimes forming a dense 10-35 cm tuft;
sheaths glabrous;
ligules 2-13 mm, scarious, decurrent, obtuse to acute;
blades 5-30 cm long, usually at least some flat and 1-4 mm wide, the remainder folded or rolled and 0.5-1 mm in diameter, adaxial surfaces with 5-11 prominent ribs, ribs usually all papillose, scabridulous, or scabrous, sometimes puberulent, outer ribs sometimes more strongly so than the inner ribs.
8-30(40) cm, 4-30 cm wide, usually open and pyramidal, sometimes contracted and ovate;
branches straight to slightly flexuous, usually strongly divergent, sometimes strongly ascending, lower branches often scabridulous or scabrous, particularly distally, with not or only moderately imbricate spikelets.
9-40 cm long, 8-30 cm wide, open, pyramidal;
branches divergent, scabridulous to scabrous.
2.5-7.6 mm, ovate to V-shaped, laterally compressed, usually bisexual, sometimes viviparous, bisexual spikelets usually with 2(3) florets, rarely with 1.
4.5-8 mm, greenish, not to somewhat imbricate.
lanceolate, acute;
lower glumes 2.7-7 mm, entire, 1-3-veined, midvein sometimes scabridulous, at least distally;
upper glumes 2-7.5 mm, 1-3-veined, lanceolate, midvein smooth or wholly or partly scabridulous;
callus hairs 0.2-2.3 mm;
lemmas 2-5(7) mm, smooth, shiny, glabrous, usually purple over less than 1/2 their surface, purple or green proximally, if green, often with a purple band about midlength, usually green or pale distally, usually awned, awns (0.5)1-8 mm, attached from near the base to about midlength, straight or geniculate, sometimes exceeding the glumes;
anthers 1.5-3 mm.
from exceeding to exceeded by the distal floret, lengths usually 5+ times widths;
lower glumes 4.3-7 mm, midveins smooth or scabridulous distally;
upper glumes 4.4-7.5 mm;
callus hairs 0.7-1.6 mm;
lemmas 3-5(7) mm, apices 4-toothed or bifid, usually mostly green, awns 3.3-6.3 mm, straight to weakly geniculate, attached within the proximal 1/3 of the lemma;
anthers (1.5)1.9-2.5 mm.
0.5-1 mm.
voucher specimens for these counts have not been examined.
4.5-13 mm;
blades 5-12 cm long, 2-4 mm wide.
= 18, 24, 25, 26-28, about 39, 52.
= 26.
Deschampsia cespitosa
Deschampsia cespitosa subsp. beringensis
Deschampsia cespitosa is circumboreal in the Northern Hemisphere, and also grows in New Zealand and Australia. It is an attractive taxon that grows in wet meadows and bogs, and along streams and lakes, from sea level to over 3000 m in cool-temperate, but not arctic, habitats.
There are widely varying opinions concerning the taxonomic treatment of Deschampsia cespitosa. Tsvelev, Aiken, Murray, and Elven (per Murray, pers. com. 2005) recommend a narrow circumscription, and consider D. cespitosa to be introduced and mostly ruderal in regions other than Europe and western Siberia. Chiapella and Probatova (2003) adopted a much broader interpretation of D. cespitosa, treating many of the species recognized in, for example, Tsvelev (1995) as subspecies. There have been no interdisplinary, global studies of the complex. The circumscription adopted here is narrower than has been customary in North America. Some of the distribution records shown, particularly those from the northern part of the region, may reflect the broad interpretation of the species.
Lawrence (1945) demonstrated that, in western North America, Deschampsia cespitosa exhibits both ecotypic differentiation and a high degree of plasticity. The following three subspecies intergrade.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Deschampsia cespitosa subsp. beringensis is primarily a coastal species, growing up to 800 m along the Aleutian chain and the southern coast of Alaska south to Sonoma County, California, and west to the Kamchatka Peninsula, Russia. Typical plants are tall, glaucous, have long ligules and spikelets, and long, narrow glumes, but in the Pribiloff Islands and at scattered locations elsewhere, they intergrade with plants that are only 15-25 cm tall and also have smaller spikelet parts (Lawrence 1945). Deschampsia cespitosa subsp. beringensis differs from D. mackenzieana primarily in its coastal distribution and lower chromosome number. It supposedly differs from D. cespitosa subsp. cespitosa in having long glumes but, as the descriptions indicate, there is considerable overlap in this and other characters. The morphological, geographic, and ecological boundaries between the two subspecies need further study.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Panicles contracted at anthesis, the branches appressed to ascending; glumes 4.5-5.8 mm long, midvein of the lower glumes scabrous distally | subsp. holciformis |
1. Panicles open at anthesis, the branches strongly divergent to drooping; glumes 2-7.5 mm long; midvein of the lower glumes smooth or scabridulous distally. | → 2 |
2. Plants often glaucous; glumes 4.4-7.5 mm long; awns usually exceeding the lemmas; plants of the northwest coast of North America | subsp. beringensis |
2. Plants not glaucous; glumes 2-6 mm long; awns exceeded by or exceeding the lemmas; plants widespread in North America | subsp. cespitosa |
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