THE YUCCEAE. 69 
parently the same thing at Monclova, in the State of Coa- 
huila. To these latter, Dr. Engelmann attached the manu- 
script name Y. rostrata, descriptive of the long-attenuate 
apex of the fruit. 
While passing between Eagle Pass and Monterey, in 
company with Professor Sargent and Mr. Canby, in March 
1900, my attention was attracted by a narrow-leaved 
Yucca that was cultivated at C. P. Diaz and in station 
yards along the Mexican International railroad, and that 
was found forming a natural low forest about Peyotes, on 
the water-shed between the Rio Grande and Sabinas, where, 
on subsequent visits, in April and August, I was able to 
study it in detail. 
Among Yuccas this is conspicuously loosely rooted in the 
soil, so that large plants are easily removed. The trunks 
vary in height from about .3 m. to an observed maximum 
of about 3 m., the usual height being about 2 m., and the 
wood is extremely soft and spongy. When the old 
leaves are removed, the diameter of the stem is usually .15 
or .2 m., and it is not dilated except where the roots start 
from the base. Older plants aresometimes branched at the 
top, but the branches remain short, so that these trees 
usually possess several subapical crowns of leaves, rather 
than a series of separated elongated branches, like those 
of many other arborescent species. 
The leaves are very numerous, radiating in every direc- 
tion from the top of the stem in an oblong or usually nearly 
globose crown some 1.25 to 2 m. in diameter, and, although 
thin, they are sufficiently rigid rarely to become arched from 
their own weight, as they are in the species of Nolina, like 
NV. longifolia, with similar foliage. They are flattened or a 
little biconvex, quickly contracted from a broad base andthen 
very narrowly lanceolate, measuring about 6 mm. at the nar- 
rowest point and 12 mm. at the widest, which is about one- 
third their length below the grooved, acute, pungent apex. 
They are somewhat glaucous, occasionally slightly twisted 
