1898] THE DEVELOPMENT OF SOME ANTHRACNOSES 87 
COLLETOTRICHUM GLCOSPORIOIDES Penz. (jigs. 15, 84); on 
orange (Citrus aurantium L). 
This disease, which was found on an orange tree in the con- 
servatories, is also said to infest plants in outdoor cultivation. 
It causes, at first, light green spots on the leaves, which become 
collapsed and brown. Upon them are situated the black fruit- 
ing pustules which occur on both the upper and under surfaces 
of the leaf. Some spots show the acervuli arranged in quite 
regular circles around the margin, surrounding more indefinitely 
located acervuli at the center. The acervuli increase rapidly 
when the leaves are placed in a moist chamber, and the conidia 
Ooze out in bright pink masses. They are rather broadly oval, 
12-16 X 5—6u, with one ortwo large oil drops. In section the acer- 
vuli, from 120-270p in diameter, are seen to be erumpent, super- 
ficial, possessing a well-developed basal stroma, which gives rise 
to short basidia. The sete, when present, are marginal, flexu- 
ous, once or twice septate, attaining a length of 130p. 
On bean stems the fungus develops an abundant loose, white, 
flocculent mycelium. The conidia ooze out in large masses, of 
a deep pink or orange color; a blackened stroma is developed 
quite abundantly, and the growth resembled that of G. fructige- 
num, of which parallel cultures were studied. Subsequent cul- 
tures, however, developed quite different characters in the colony 
than those of that species. The compact center developed in 
G. fructigenum is not seen in Col. gleosporicides. From the small 
central point of the colony of the latter species the mycelium 
radiates in from two to five directions. The branching of the 
mycelium is more or less suppressed at the center until the myce- 
lium attains a growth some distance from the center. It there 
branches abundantly, the branches spreading out ina fan-shaped 
growth. These marginal tufts for a time remain quite distinct, 
but in older colonies well supplied with nutriment they mingle 
more or less, forming a continuous circular margin. The clear 
Spaces at the center usually remain.. The fruiting clusters 
appear in a circle some distance from the center. More or less 
of a stroma is developed in connection with the acervuli, so that 
