HITCHCOCK—MEXICAN GRASSES. 981 
17. Aristida wrightii Nash in Small, Fl. Southeast. U. S. 116. 1903. 
Type locality, ‘Dallas, Texas,’’ the type specimen collected by Reverchon (no, 
1061). 
RanGE: Southwestern United States to southern Mexico. 
HERBARIUM SPECIMENS FROM MExIco: 
Pursia: Esperanza, rocky hill, Hitchcock 6487. Tehuacdn, limestone hills, 
Pringle 8592. 
18. Aristida fendleriana Steud. Syn. Pl. Glum. 1: 420. 1854. 
Type locality, New Mexico, the type specimen collected by Fendler (no. 973). 
Rance: Southwestern United States to central Mexico. 
HERBARIUM SPECIMENS FROM MEXIco: 
Lower Cautrornia: Topo, Orcutt 1146. 
Coanuita: Diaz, dry mesas, Pringle 9037. 
19. Aristida longiseta Steud. Syn. Pl. Glum. 1: 420. 1854. 
Type locality, New Mexico, the type specimen collected by Fendler (no. 978). 
RANGE: Southwestern United States and northern Mexico. 
HERBARIUM SPECIMEN FROM MEXICO: 
CuInvAHUA: Plains near Chihuahua, Pringle 473. 
60. STIPA L. Sp. Pl. 78. 1753. 
KEY TO THE SPECIES. 
Awn strongly plumose, bent once........... ceceeeeeeeeees 1. 8. speciosa. 
Awn not plumose, often scabrous or - pubescent. 
Lemma or base of awn long-pilose. 
Fruit 3 mm, long, pilose at summit................... 15. S. tchu. 
Fruit 7 mm. long, pilose all over. 
Awn with 1 bend; plant about 0.5 meter high.... 2. S. parishit. 
Awn with 2 bends; plant about 1 meter high...... 3. S. coronata. 
Lemma more or less pubescent, but not long-pilose. 
Fruit 3 mm. long; awn very slender, flexuous......... 16. S. tenuisissima, 
Fruit more than 3 mm. long. 
Glumes about 3 cm. long, subequal; lemma about 
1.8cm., long.................22..2..222-22-. 4. S. melanosperma. 
Glumes shorter. 
Panicle open, the branches long and spreading. 
Fruit short-pilose below, glabrous and 
punctulate-roughened above, with 
a constricted neck ciliate at sum- 
mit. 
Fruit 1 cm. long..................... 5. 8. leucotricha. 
Fruit 5 mm. long.................... 6. 8. trochlearis. 
Fruit short-pilose all over. 
Mature fruit dark-colored, turgid, 8 
mm. long, the hairs brown.... 8. S. pringlei. 
Mature fruit light-colored, slender, 5 
to 6 mm. long, the hairs white. 7. S. eminens. 
Panicle narrow, the branches ascending or 
appressed. 
Mature fruit dark-colored, turgid, the 
hairs brown. 
Fruit 4 mm. long.................... 9. S. mucronata, 
Fruit 6 mm. long.................... 10. S. virescens. 
