286 Part III. Chapter 3. 
arborescens (S. Nevada, S. E. California), Yucca mohavensis (S. California, S. Nevada), Hesperoalo& 
parviflora (Arizona), Yucca radiosa, Yucca macrocarpa (S. Arizona, S. New Mexico), Yucca brevi- 
folia (S. Arizona). 
The papaveraceous genus Aunnemannia of Mexico is related to the genus 
Eschscholtzia of California and Great Basin. Dalea is represented by numerous 
species on the table-land of Mexico and. by eleven species in Arizona and the 
Fig. 8. Yucca Treculcana Carr. Chihuahuan Desert Region, Mexico, as seen near the aim; 
’ 
of the Sun northeast of the City of Mexico. After Contributions from the U. S. National eo 
barium V, Plate XXXVII. 
Great Basin. Likewise Zarrea mexicana is common. Among the Kosaccat, 
we find Coleogyne, Cowania, Fallugia only in Mexico, the Great Basin and 
California, Cercocarpus perhaps also is a Mexican ET of extensive northern 
distribution. Brickellia a genus of the Compositae- Eupatoriaceae which includes 
many species in Mexico is represented by one species in the Atlantic au 
. Mes also in Texas and the Great Basin. As representatives of the souther® 
contingent (not necessarily Mexican) may be mentioned: 
Alkali formation. 
Thelypodium Nuttallii (= T, torulosum), Cleomella parviflora. 
