118 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.13 



Aristida Purpusiana Hftchc, C.N.H. 17:276. 1913. 

 San Jose del Cabo, February 17, Dawson 1211. 

 Known only from southern Baja California; the type from San Jose 

 del Cabo. 



BouTELOUA BARBATA Lag., Cienc. 24:141. 1805. 



San Jose del Cabo, February 17, Dawson 1182, Punta Frailes, Cape 

 Frailes, February 16, Dawson 1119. 



Southwestern United States and northern Mexico; type from Mexi- 

 co. It is most abundant through the middle and low elevations of the 

 Grama Grasslands, where it often takes its place as one of the codomi- 

 nants. The cape specim.ens show no significant differences from main- 

 land material and the population from which they come may be a recent 

 or post- Pleistocene development. 



BouTELOUA CURTIPENDULA (Michx.) Torr. in Emory, Notes Mil. 

 Reconn. 154. 1848. 



San Jose del Cabo, February 17, Dawson, 1207. Agua Verde Bay, 

 March 10, Rempel 136. 



Widely distributed in North America from Canada to Central 

 America. It is most abundant in the Grama Grasslands of the semiarid 

 southw^estern United States and northern Mexico, where it is one of the 

 codominating gramas. It is also in South America, occupying similar 

 habitats. The type locality is the Limpio Mountains, Texas. The Feb- 

 ruary collection is in anthesis, that of March already seeded. The species 

 is apparently capable of flowering twice a year. 



Cenchrus Palmeri Vasey in Brge., Proc. Calif. Acad. Sci. II, 

 2:211. 1889. 



San Jose del Cabo, February 17, Dawson 1181. 



This strongly spined burr grass is endemic to the California Gulf 

 Region w^here it is know^n from the southern half of the peninsula, on 

 the adjacent islands, and around Guaymas, Sonora, the latter being the 

 type locality. It forms extensive stands along the stationary dunes of the 

 outer peninsular coast and is obnoxious because of the strong sharp spines 

 on the large fruits. 



Eragrostis viscosa (Retz.) Trin., Mem. Acad. Petersb. Sen VI, 

 Math. Phys. Nat. 1:397. 1830. 



San Jose del Cabo, February 17, Dawson 1160. 



The Cape District of Baja California and India; the type from 

 Malabar Beach. Obviously an introduction, perhaps in ballast. 



