1907] BURLINGAME— SPORANGIUM OF OPHIOGLOSSALES 51 



the germination of the members of a tetrad which failed to separate 

 in the usual way. Possibly the lack of a thick wall around the young 

 tetrad is responsible for the continued growth; at any rate, no indica- 

 tion of the germination of ordinary thick-walled spores was observed, 

 unless jig. jo be interpreted as such. Not unlike this is the produc- 

 tion of more than four microspores in some angiospcrms, but so far 

 as I am aware similar phenomena have been reported in only oae 

 homosporous plant. In an account of the germination of the oospore 

 of Coleochaete, Allen shows that reduction takes place with the first 

 division; the spores thus produced germinate and cooperate to pro- 

 » duce a multicellular mass of gametophytic tissue. Each cell of this 



* mass of tissue eventually produces a zoospore which gives rise to the 



^ ordinary vegetative phase of the plant. Wille has shown ('86) that 



, in certain angiosperms by a suppression of the second maiotic division 



a mother cell may give rise to two microspores only instead of the usual 

 four. Since in at least the majority of plants the unlike elements of 

 the bivalent chromosomes are separated in the first division of the 

 mother cell, there seems to the writer no valid reason, other than that 

 imposed by the available food supply and the ordinarily thick walls, 

 why any number of spores more than two may not arise from a mother 

 cell. In a discussion of many-spored asci Overton (:o6) has 

 recently shown that the number of divisions in the ascus is immaterial 

 so far as the essential nature of the resulting spores is concerned. In 

 this connection the recent experimental work of N£mec (:o6) is of 

 considerable interest; by subjecting staminate flowers to the action 

 of chloroform vapor he secured pathological conditions closely paral- 

 leling those herein described. His attempts to germinate these bodies 

 should yield interesting results. 



SUMMARY AND COMPARISON 



The following tabular form of statement will serve to contrast com- 

 pactly the three genera of Ophioglossales as to their sporangia. 



Ophioglossum Helminth ostachys Botrychium 



I. Outer wall and corre- The essential parts from Like preceding but 

 spending parts of the tapet- a single superficial cell. smaller contribution of 



f 



um and the sporogenous 

 tissue from one or two su 

 Perficial cells of a sporangi 



ghboring 



