HITCHCOCK—MEXICAN GRASSES. 975 
Branches of panicle short, erect, some flower- 
bearing branchlets near the base. 
Blades flat.........--.------2--- eee ee 11. A. spadicea. 
Blades involute........----.---.-+.-- 12. A. arizonica, 
Neck of awns not twisted. 
Panicle open, the branches divaricately 
spreading or reflexed, naked below... 18. A. divaricata. 
Panicle contracted, the main branches not 
stiffly spreading or divaricate. 
First glume slightly longer than the 
second ..--...-.--2------ eee ee 14. A. liebmanni. 
First glume shorter than the second. 
Panicle branches capillary, flexu- 
ous. 
Panicle narrow, only the main 
branches flexuous; leaves 
mostly basal . .- . 15. A. berlandiert. 
Panicle rather diffuse, all ‘the 
branches flexuous; leaves 
scattered ....--.-......--- 16. A. micrantha, 
Panicle branches short, stiff, ascend- 
ing. 
First glume slightly shorter than 
the second; panicle vir- 
gate; blades elongated, 
more or less scattered... - . 17. A. wrightit. 
First glume about half as long as 
the second; panicle few- 
flowered, not  virgate; 
leaves mostly basal. 
Awns 4 to6cm. long ........ 18. A. fendleriana. 
Awns about 10 cm. long....... 19. A. longiseta. 
1. Aristida jorullensis Kunth, Rév. Gram. 1: 62. 1829. 
Type locality, ‘‘in planitie calidissima Mexicana, Playas de Jorulla.”’ 
Ranas: Pacific slope of Mexico and Central America. 
HERBARIUM SPECIMENS FROM MEXICO: 
Sonora: Alamos, rocky hillside, Rose, Standley & Russell 12756. 
SmvaLoa: Mazatlin, dry hill, Rose, Standley & Russell 13681. Culiacan, Cerro 
Colorado, Brandegee in 1904. 
Tepic: Acaponeta, dry hill, Rose, Standley & Russell 14303. 
Cotma: Manzanillo, Palmer 1084 in 1890. Tecomén, along railway, Hitchcock 
7048. Alzada, gravelly soil, Hitchcock 7075. Colima, Orcutt 4569. 
Guerrero: Acapulco, Palmer 36 in 1894. 
2. Aristida schiedeana Trin. & Rupr. Mém. Acad. St. Pétersb. VI. Sci. Nat. 3: 
120. 1840. 
Aristida orcuttiana Vasey, Bull. Torrey Club 18: 27. 1886. 
Type locality, ‘Mexico, prope Jalapam,”’ the type specimen collected by Schiede 
(no. 909). 
Rance: Southwestern United States to southern Mexico. 
HERBARIUM SPECIMENS FROM MEXICO: 
Lower Caurrornia: La Chuparosa, Brandegee in 1897. Sierra de San Francis- 
quito, Brandegee in 1899. Hansen’s ranch, Orcutt 007. 
