CONTRIBUTIONS TO WESTERN BOTANY No. 17 23 
either very thin or very rigid, and two to four feet long, almost flat or deeply 
sulcate. Then the flowers vary from typical to almost rotate and with or 
without a tube. You find flowers two inches and flowers four inches long. 
The whole pseudo-forest region seems to be a unit in its Yucca vegetation. 
You do find, here and there, a few Y. elata, but this species is not at all 
related to the edible-fruited Carnerosana. Now what is a person going to do? 
imperceptibly into Yucca baccata. There seems to be a gradual intergrada- 
ion from Yucca Schottii to the macrocarpa of the plains, and from that to 
. "M ohavensis of California. I have already called attention to the inter- 
breeding of Mohavensis with baccata. I have now been studying closely 
for seven years the various forms of Yucca and I find that Y. Mohavensis 
very often has the pear-shaped flowers of baccata though most of the forms 
have nearly rotate flowers. The panicles of Mohavensis are almost always 
sessile among the leaves, as are those of baccata, but baccata never has a 
trunk, while all the others have a trunk at ma turity at least. There is no 
way to keep up the species of Yucca as interpreted by Trelease Sitted to 
ignore all ecological facts and rest arbitrarily on variable characters. I 
adjacent coe there is no telling the forms apart by the leaves. Trelease 
forms of flowers of Y. Treculiana without manifest tube into 
Yucca, and his with tube into Samuela, but there is a gradual intergrada- 
tion, and no possibility of separating them in the field, by any floral or 
vegetative character. 
Calochortus Nutallii T. & G. on the banks of the Gila river near 
Silver City, N. M., May 4, 1930. 
Sisyrinchium Arizonicum Rothr., Rock Springs, Texas, April 16, 1930. 
Iris Missouriensis Nutt. Cloudcroft, N. M., May 
Nolina Texana Watson. Hope, N. M., May 2, 1930; Valentine, Texas, 
April 28, 1930. 
Agave heteracantha Zucc. Hot Springs, Pee April 24, 1930. This is 
very common on limestone areas along the Rio Grande, ocurring in great 
masses. It was just coming into bloom. The flowers are a very deep 
le. 
purple 
Nothoscordum striatum Kunth. Rock Springs, Texas, April 17, 1930. 
This appears to be quite common but was hardly in bloom. 
