GRASS FAMILY 87 



Spikelets placed flatwise to the rachis, all with 2 glumes. 



Spikelets several-tlowereil 67. Agropyron. 



Spikelets l-flowered; spikes very slender. 



Lemma awnless 65. Lepturus. 



Lemma awned 66. Scribnebia. 



Spikelets, at least some of them, in 2 "s or 3 's at each joint of the rachis. 



Spikelets 1-flowered, not all alike, in 3's, the lateral pair pediceled 68. Hordeum. 



Spikelets 2 to 6-flowered, all alike, usually in 2 's. 



Glumes minute or wanting; spikes loose 71. Hystrix. 



Glumes about as large as the lemmas; spikes dense. 



Axis of spike continuous, not disarticulating at maturity; glumes broad or narrow 



but not greatly elongated 69. Elymus. 



Axis of spike disarticulating at maturity; glumes usually setaceous and elongated. 



70. SiTANION. 



Trike I. ANDROPOGONEAE. 

 1. IMPERATA Cyrillo. 



Spikelets 1-flowered. in pairs, nil alike, iiiieqnally pedicellate, articulated with 

 the pedicels, densely clothed with long silky hairs. Ghime.s 2, membranaceous, 

 long-villous. Sterile and fertile lemmas membranaceous, glabrous, the latter 

 narrow, its palea broad, truncate, toothed, surrounding the ovary. Erect 

 perennial grasses with densely villous spike-like terminal panicles. — Warm re- 

 gions of the world, about 5 species. (The Italian naturalist Ferrante Imperate.) 



1. I. hookeri Kupr. Culins erect from creeping rhizomes, 3 to 5 feet high, 

 glabrous; sheaths glabrous; ligule long-villous; blades elongated, the lower 

 narrowed at the long conduplicate base, 4 to 6 lines wide, acuminate, glabrous, 

 the upper shorter, the uppermost much reduced; panicle dense, 6 to 12 inches 

 lono: pale or tawny, or somewhat rose-tinted, soft, silky; spikelets about II/2 

 lines long, clothed Avith hairs twice as long. 



Desert regions, from southern California to New Mexico and sovith into Mexico. 



Locs. — Tulare Co., Palmer 2748 in 1892; Inyo Co., Coville 4' Funston 219, 240; San Ber- 

 nardino, Parish Bros. 1031; Colorado Desert, Wilder 1077. 



Ref. — Tmperata hookeri Rupr.; Andersson, Of v. Vet. Akad. Forh. 12: 160. 18.55. 



Ere.mochloa leersioides Hack, in DC. Monogr. Phan. 6 : 264. 1889. Ischae- 

 tiiiim leersioides Munro, Proe. Am. Acad. 4: 363. 1860; Thurb. in Wats. Bot. Cal. 

 2: 262. 1880. Thurber states that this was "collected in San Francisco, near a 

 Chinese Warehouse, Bolander." It is a native of China and has not since been 

 collected. 



2. HOLCUS L. 



Spik-elets in 3's, terminating the branchlets of the panicle, the central spike- 

 h'l l-tlowere<l, sessile, perfect, the lateral pedicellate, staminate. Glumes 2, 

 hard and shining. Sterile lemma hyaline. Fertile lemma small and thin, bear- 

 ing a geniculate awn. Palea minute. Annual or perennial grasses with ter- 

 minal, open or contracted panicles. — Species 2, natives of the Old World, one, 

 H. Sorghum L. (Andropogon sorghum Brot. ; Sorghum vulgare Pers.), being 

 widely cultivated under the name of Sorghum, Cane, Milo Maize, Durra, Kafir 

 etc. (An oil] Latin name for a grass, probably from the Greek holcos, attractive.) 



1. H. halepensis L. Johnson Grass. An erect glabrous robust plant, with 

 extensively creeping rhizomes; culms 2 to 4 feet high; blades flat, 3 to 9 lines 

 wide, the midrib prominent, white; panicle 6 to 10 inches long, more or less 

 spreading; fertile spikelets aliout 2V-; lines long, the glumes pubescent, becom- 

 ing glabrate and shining; staminate spikelets narrow, 2 lines long, on pedicels 

 IVi; lines long, the glumes membranaccons. nerved, glabrous. 



