182 BOTANICAL GAZETTE [SEPTEMBER 
shown in fig. 2 grew in a moist situation, where the water of an 
arroyo was impounded by adam. The plant is in its early spring 
condition, the rosette having survived the winter. The root 
system is of the generalized type. The laterals near the surface 
are especially well developed, sometimes exceeding the tap root 
in length. The specimen shown in fig. 3 is from a dry, gravelly 
ridge in the Dysodia-Ephedra 
association. The impoverished 
condition of the plant is shown 
by the weak development of 
both root and shoot. Here the 
tap root is relatively the more 
important. 
Allocarya crassisepala.—This 
is one of the most common 
annuals of the mesa and 
arroyos and is a ruderal in a 
number of associations. The 
plants vary very greatly with 
the soil conditions in both root 
and shoot. The plant shown 
in fig. 4 grew in moist soil in 
the bottom of an arroyo and 
bore numerous prostrate 
branches. The root system 
was superficial and consisted of 
a short tap root which soon 
“Fic. Biscutella Wislizeni «became horizontal, and - 
number of long, b 
laterals arising about an inch below the surface of the soil. The 
‘plant shown in fig. 5 grew in dry soil and had a tap root relatively 
= "hig a: and vertical, with poeta and less numerous 
canescens. —This plant i is common ina number of a 
