HITCHCOCK—MEXICAN GRASSES. 323 
3. Deschampsia elongata (Hook.) Munro; Benth, Pl. Hartw. 342. 1857. 
Aira elongata Hook, Fl. Bor. Amer. 2: 243, pl. 288. 1840. 
Type locality, ‘‘Sandy islands of the River Columbia,”’ the type specimen collected 
by Douglas. 
Rance: Alaska to southern Mexico. 
HERBARIUM SPECIMENS FROM MEXICO: 
México: Sierra de las Cruces, wet banks, Pringle 4743. Federal District, Pringle 
13244. 
4. Deschampsia liebmanniana (Fourn.). 
Deyeuxia liebmanniana Fourn. Mex, Pl. 2: 106. 1886. 
Type locality, not definitely given, three collections cited as follows: “In monte 
Orizabensi * * * (LieBM.n.610 * * * );insummoCofredePerote, * * * 
(HauHN); prope Tlapacoya (HaHN).”’ 
RanGeE: Southern Mexico. 
HERBARIUM SPECIMEN: 
México: Nevado de Toluca, by brooks, Pringle 4242. 
5. Deschampsia straminea sp. nov. 
Culms cespitose, sometimes decumbent or rhizomatous at base, glabrous, 20 to 35 
cm. high; leaves mostly basal, stramineous, shining, glabrous except the margins of the 
blades; sheaths loose and papery; ligule about | cm. long, thin; blades involute, some- 
what spongy in texture, pungent-pointed, 5 to 10 cm. long or the uppermost shorter; 
panicle purple, ovoid in outline, 7 to 12 cm. long, open, the lower branches in twos or 
threes, 2 to 5 cm. long, slender, flexuous, spreading, smooth; spikelets somewhat 
crowded toward the ends of the branches, 2-flowered, the rachilla produced as a hairy 
bristle; glumes equal, about 7 mm. long, acute, narrowed below, broadest about the 
middle, glabrous, slightly scabrous on the keels above, more or less 3-nerved, purple, 
yellowish toward the apex; lemma thin, glabrous, 4 mm. long, 5-nerved, 4-toothed at 
the thin or erose apex, the awn attached just above the base, straight, slightly exceed- 
ing the lemma; callus and rachilla joint long-pilose, the hairs 2 mm. long, the prolon- 
gation of the rachilla about half the length of the lemma. 
This species is allied to D. caespitosa, but the spikelets are larger and the plants 
touter in proportion to their height. 
Type in the U. S. National Herbarium, no. 691237, collected on rocks, alpine region 
sof Ixtaccihuatl, Mexico, October, 1905, by C. A. Purpus (no, 1619). 
The only other collection seen is from ‘‘Rocky slopes, alpine region, Mt. Orizaba,”’ 
Purpus 3018. 
76. TRISETUM Pers. Syn. Pl. 1: 97. 1805. 
KEY TO THE SPECIES. 
Plants annual; panicle narrow, interrupted............--.----- 3. 7. californicum. 
Plants perennial. 
Panicle spike-like, often interrupted at base. 
. Lemma and awn glabrous or nearly 80.........-------- 1. T. spicatum. 
Lemma villous; awn somewhat plumose........------ 2. T. rosei. 
Panicle open or, if narrow, not spike-like. 
Second glume broad, abruptly acute. 
Blades mostly basal, involute, capillary, flexuous.. 8. T. filifolium. 
Blades scattered, flat. 
Plant tall and stout, 1 to 2 meters high; panicle 
large; 15 to 30 cm. long.............---- 10. T. virletit. 
Plant low and slender, mostly less than 0.5 
meter high; panicle narrow, mostly less 
than 10 cm. long...........---+-+--0--- 9. T. fournieranum. 
