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Arthur and Holway: VIOLET RUSTS OF NORTH AMERICA. 637 
This species shows remarkable variability, especially in size 
of the spores, and in the thickness and markings of their walls. 
These differences come out most strikingly when comparing a 
series of specimens. There is also considerable variability in 
the form of the spores, as shown in Figs. 5 and 6, both taken 
from the same specimen, but it is such as one may expect to 
find in many other species of rusts. 
If almost any specimen of violet rust be compared critically 
with an European specimen, the greater size of the teleutospores 
in the former is likely to attract attention. This is the basis of 
the species proposed by Cooke, Puccinia hastate. A specimen 
collected by W. C. Blasdale on Vola cognata at Sisson, Calif. 
(Figs. 5 and 6), has been compared with the type material of 
P. hastate at the Kew Herbarium, through the kindness of Mr. 
Massee, and found to agree very closely. The greater size of 
the teleutospore in the American material generally is notice- 
able, and this difference extends to the uredo and ecidial stages 
as well, although not usually so pronounced. In the case of 
an ecidium on Vzola pubescens, collected at Decorah, Iowa, in 
1882, Farlow has made the comment :—‘‘ Spores somewhat 
larger than in the European specimens; this may be the 
fEcidium of Puccinia hastate Cke.” (on the label in Ellis’ N. 
Amer. Fungi, no. 1007). If size of spores is to be taken as 
valid basis for separating species, there is no question that the 
American form shows a strong claim to rank as autonomous. 
The claim, even on that assumption, is much weakened, how- 
ever, by the great range between the smallest and largest of 
the American specimens, indicating a decided capacity for vari- 
ability rather than a fixed form. 
A peculiarity of the American violet rust, that in the case of 
European specimens we have not seen mentioned and have not 
observed, is the frequently tuberculate sculpturing of the teleu- 
tospores. Burrill (Paras. fungi Ill.: 174) makes this a diag- 
nostic character, but in a wide series of specimens one does not 
always meet with it. With most observers the spores would 
generally be rated as smooth like the European form. The 
true character of surface markings can be best studied by ob- 
serving the spores without addition of fluids. In this way it is 
easy to see that the markings are small papille, sparingly dis- 
tributed, and chiefly appearing on the upper half of the spore. 
A closer study reveals the interesting fact that when no eleva- 
