THE LARCH CANKER 43 
spores from the ascus of this species is between 10 and 
15 mm. In a damp chamber such as that described, the 
spore-ejection may take place very rapidly, and from two 
small apothecia, measuring 1-25 mm. and 1-5 mm. respec- 
tively in diameter, 104 spores were found to have been 
ejected in2 minutes. In a dry atmosphere the asci cease to 
shed their spores, a fact which is no doubt correlated with 
the closing of the apothecia in dry weather. 
The spores may germinate in either of the two following 
ways: (i) The spores first divide by one, or less commonly 
eutace. 
) W 
Po 
aA Bb ¢ 
On 
i 
Fic.*20.—Spores and germination: a, spore, showing nucleus and 
vacuoles ; B, germinating at both ends; c, two germ tubes at one end ; 
D, segmentation; E,-F, G, methods of germination. 
more septa which are put in at right angles to the long 
axis of the spore (fig. 20, D, E). The first of these may be 
completed twenty hours after the ejection of the spore. 
When the spore becomes divided into three segments 
(fig. 20, F) these are usually unequal, one being nearly half 
the size of the whole spore ; a third septum may then be 
formed in the larger cell. The germ tubes may arise in 
many different ways. Most commonly one grows out from 
each end of the spore, or one of them may originate near 
the middle septum, but cases in which three or four germ 
tubes arise from a single spore are not infrequent. (ii) The 
spore may give rise to germ tubes without first becoming 
