1913] LAND—EPHEDRA 445 
limiting altitude of Ephedra, is compact. Since the tendency of 
soil movement is to force the plant constantly toward lower alkti- 
tudes, if it were not for underground lateral branching, Ephedra 
would first be driven from the higher slopes and ultimately from 
the region. 
If Ephedra does produce seeds in this region they are promptly 
destroyed by small animals. Not many seedlings of pine and spruce 
are found, although great quantities of seeds mature. Spruce seeds 
are eaten by squirrels as soon as they ripen and long before they 
fall. Great numbers of pifion jays visit the region in autumn and 
feed on the nuts of Pinus edulis. However, pifions and spruces 
are so abundant that enough seeds to keep up the forest are over- 
looked. It is regretted that observations cannot soon be made to 
determine if Ephedra really does set seed in this region. 
Most of the branches of this Ephedra fall at the close of summer, 
a regular absciss layer being developed at each node. In September 
the ground under the plants is green with the fallen branches. 
Ephedra nevadensis was found in western Colorado only on the 
most bleak and unstable slopes and does not seem to be widely dis- 
tributed. No seedlings were found. The plant propagates itself 
vegetatively by shoots, which, after having been overthrown and 
buried by talus, take root, erect their tips, and send out erect lateral 
branches; and also by means of underground rhizomes which are 
given off from older buried shoots. These rhizomes either send 
up branches or erect their tips or they may do both. They may 
also send out other rhizomes. Assuming the absence of seeds, 
Ephedra owes its preservation in this region to the rhizome-forming 
habit. If it were not for this habit and if other factors which 
are not apparent at present did not intervene, soil movement would 
ultimately force the plant below the lower limiting stage and 
cause it to disappear entirely from the region. 
UNIVERSITY OF CHICAGO 
