Page:New species of grasses from South America.djvu/2

196 base, firm, glabrous beneath on the lower part, very scabrous toward the tip, scaberulous on the upper surface, 40 to 60 cm. long (the uppermost about 20 cm.), about 4 mm. wide at base when flat, gradually narrowed to a fine point; panicle dense, 30 to 50 cm. long, 5 to 8 cm. wide, purplish, the axis mostly hidden by the overlapping branches, terete and glabrous below, angled and scabrous above, the branches appressed or ascending, fascicled, the longer ones naked at base, the shorter ones spikelet-bearing to base, the branches and branchlets more or less hispidulous at base, the ultimate branchlets rather slender, the lateral pedicels appressed, 1 to 2 mm. long; spikelets (only the pistillate seen) mostly 4 to 6-flowered, about 1.5 cm. long (excluding awns), the uppermost floret much reduced; glumes narrow, hyaline, 1-nerved, gradually acuminate, a distinct internode between the two, the first about 8 mm. long, the second about 10 mm. long; rachilla readily disarticulating between the florets, the joints about 1 mm. long, long-pilose, the joint below the lower floret about as long as the others; lemma rounded on the back, about 7-nerved, rather sparsely villous all over, the hairs ascending, about 3 mm. long, the tip 3-lobed, the lateral teeth extending into long very slender awns (total length about 9 mm.), the midnerve flat below, somewhat curved outward, extending into a slender flat awn about 2 cm. long, the length of lemma to base of awn about 4 mm.; palea narrow, 2-keeled, scabrous-ciliate on the keels, about as long as the lemma; stamens wanting; ovary 1.5 mm. long; stigmas 1 mm. long, plumose nearly to base; caryopsis 2.5 mm. long, acute at base.

Type in the herbarium of the Field Museum of Natural History, No. 517,715, collected on a shrubby slope, at about 3000 meters altitude, Yunahuanca, Peru, June 16–22, 1922, by Macbride and Featherstone (No. 1205).

The only other specimen seen is from Torontoy, Urubamba Valley, Peru, at an altitude of 2400 meters, June 10, 1915, Cook & Gilbert No. 1189, said to be called nihuaichu.

This species differs from L. hieronymi (Kuntze) Pilger in the more dense purplish panicle and the longer glumes and lemmas. The glumes of the former are 5 to 7 mm. long, and the lemmas, to the base of the awn, 2.5 to 3 mm. The awns are white and flexuous, while in L. peruvianus they are purple and nearly straight. Some of the florets of the type specimen of L. peruviana are attacked by insects, forming small galls.

Lamprothyrsus hieronymi and its four varieties are from Argentina and Bolivia. Mandon's No. 1360 from Sorata, Bolivia, and a specimen from Province Jujuy, Argentina, collected in 1916, by S.W. Damon, are this species. The last two and also Fiebrig's No. 2099 (type of L. hieronymi tincta Pilger) are pistillate. The type of L. hieronymi (Triraphis hieronymi Kuntze) is staminate.

Culms cespitose, erect, glabrous, 2-noded, 20 to 30 cm. tall; sheaths, slightly roughened; ligule on the culm leaves 2 to 3 mm. long, obtuse, firm; blades capillary, involute, glabrous, 5 to 15 cm. long; panicle elliptic, 3 to 4 cm. long, purple, rather compactly few-flowered, the axis, branches