HITCHCOCK—-MEXICAN GRASSES. 827 
HERBARIUM SPECIMENS FROM MEXICO: 
CuinuanuA: Colonia Garcfa, Nelson 6198. 
Duranco: Otinapa, Palmer 343 in 1906. Guanacevi, Nelson 4735 (this specimen 
appears to be K. cristata longifolia Vasey). 
FEDERAL District: Above Santa I'é, Pringle 9608. 
WirnHovut Locauity: Liebmann 609. 
79. AVENA L. Sp. Pl. 79. 1753 
KEY TO THE SPECIES. 
Lemmas glabrous or nearly 80...........-. 020-2002 eee eee eee eee eee 2. A, sativa. 
Lemmas pubescent with long brown hairs. 
Teeth of lemmas acute, not awned..............2.-..2...2-4..-- 1. A. fatua. 
Teeth of lemmas awned; pedicels subcapillary............0..... 3. A. barbata. 
1. Avena fatua L. Sp. Pl. 80. 1753. WILD oar. 
Type locality, ‘‘in Europae agris inter segetes.”’ 
Rance: Weed throughout North America, especially on the Pacific slope, introduced 
from Europe. 
HERBARIUM SPECIMENS FROM MEXICco: 
Cuiuvuauua: Sanchez, along railway, Hitchcock 7699. 
CoanHuIta: Saltillo, waste places and cultivated fields, Palmer 8 in 1898. 
San Luis Porosi: San Luis Potosf, edge of field, Hitchcock 5694. 
QUERETARO: Querétaro, edge of field, Hitchcock 5859. . 
Mexico: Toluca, rocky hill, Hitchcock 6891. 
Puresia: Tehuacdin, Hitchcock 6053. 
Oaxaca: Las Sedas, Conzattt & Gonzdlez 263. 
2. Avena sativa L. Sp. Pl. 79. 1753. Oat. 
Type locality unknown, the species named from cultivated plants. 
Rance: Commonly cultivated and occasionally escaped. 
HERBARIUM SPECIMEN FROM MEXICO: 
FreperavL District: Volunteer along trolley, Hitchcock 5887. 
8. Avena barbata Brot. Pl. Lusit. 1: 108. 1804. 
Type locality, Portugal. 
RanGE: Pacific coast of United States and Lower California. 
HERBARIUM SPECIMEN FROM MEXICO: 
Lower Cairornia: Guadalupe Island, Palmer 668 in 1889. 
80. TRISTACHYA Nees, Agrost. Bras. 458. 1829. 
KEY TO THE SPECIES. 
Panicle branches shorter than the spikelets, rarely slightly longer, 
appressed, the spikelets 3 cm. long; terminal portion of awn 
3 to 6 cm. long, flexuous................0220 2... 020220005 1. T. avenacea. 
Panicle branches, at least the lowermost, much longer than the 
spikelets, these, excluding the awns, not over 2 cm. long; 
terminal portion of the awn 0.5 to 1.5 cm. long, straight. 
Plants robust, 1.5 meters or more high; blades 5 to 10 mm. 
wide; panicle branches capillary, elongated and lax.... 3. T. laza. 
Plants slender, about 1 meter high; blades 3 to 4 mm. wide; 
panicle branches slender but not capillary, ascending.. 2. T. angustifolia. 
1. Tristachya avenacea (Presl) Scribn. & Merr. U.S. Dept. Agr. Div. Agrost. Bull. 
24: 23. 1901. 
Monopogon avenaceus Presl, Rel. Haenk. 1: 325. pl. 44. 1830, 
Type locality, “‘Mexico.’’ 
