SPORE DISSEMINATION 35 
ing the point is caused largely by the fact that it was entirely over- 
looked in the early part of my investigation. Plate 2 will show 
some of the species in which it is known to occur. 
When mature perithecia are ruptured under the cover-glass, 
the asci escape in the same manner as in the genus /leurage, 
but here there is a much more conspicuous effect of osmosis. 
The asci rupture in rapid succession and the membranes stretch 
out with such force and such rapidity as to keep the entire field in 
constant agitation for a considerable length of time. It is rather 
exceptional, however, to find a membrane rupturing normally 
under such circumstances. They generally remain stretched for 
a time and finally either rupture at some point in the lateral wall 
or gradually contract again when the membrane deliquesces and 
disappears entirely. 
The distance to which the spores are ejected in this genus has 
not been studied with any degree of accuracy. But judging from 
the case of S. Dakotensis, where hundreds of asci have been seen 
ejecting their spores in water, the force of membrane rupture here 
is about the same as the force of ascus rupture in the species of 
Pleurage studied. (Pl. 2. f. 7.) 
There appears to be considerable variation in the different 
species in reference to the progress of the asci through the ostio- 
lum. In S. intermedia two and three asci may stretch out at once. 
Usually one is in advance of the others, but still some portions of 
three will be seen moving out at one time. In S. Zeporiza one at 
a time appears to be the rule, to which an exception has never been 
noticed either in this species or S. Dakotensis. The phenomenon 
has been observed but once in the first species, several times in 
the second, and twice in the last, with which a very thorough 
series of observations were made. 
The rapidity with which the successive membranes appear at 
the ostiolum in S. Dakotensis is sometimes almost incredible. 
Several will often stretch out in a minute with perfect regularity 
and in absolute single file. Nearly two days were spent in study- 
ing the South Dakota specimens of this species when they became 
mature ; the results obtained were most astonishing when com- 
pared with the genus Pleurage. 
Observations were made the first day on three perithecia between 
