AECIAL STAGE OF ALSIKE CLOVER RUST 
46 : 
peared April 26, 1916, and the aeciospores proved viable. When 
on the petiole, they were located at or below the lower half. 
Size — the patches vary from 0.1 mm. to 150 mm. in length and 
tend to the elliptical, near or remote from pycnia; height, 182 
Mu. (20 measured), width, 172 Mu.; peridial cells length, outer 
Fig. 90. — An Aecium on Alsike Clover. For measurements see Tables I 
and II. 
22 Mu. (10 averaged), inner 15 Mu. (10 averaged), width, 14 
Mu. (10 averaged). Lumen, length 12.5 Mu., width, 10 Mu., 
outer wall, transversely striated 2. 5-3. 5 Mu. thick ; inner w T all 
minutely verrucose, 0.7-1. 5 Mu. thick. The cups present a white 
