,QO NATURAL HISTORY BULLETIN. 



D I S C O M Y C E T E S. 



Family II. GYiMNOASCE.E Baranitz. 

 Sub-faniilv I. EXOASCE^ Sadeb. 

 Tapiirixa. Asci polyspori, cellula basilari carentes, rariiis in.structi-. 

 Exo.\scrs. Asci Mib-octospori, cellula basilar! instriicti, rariiis carentes. 



In a recent publication ( Zopf, '90) I tind: 

 Order G Y M N O A SC A C E .E. 

 Family I. SACCUAROM YCETES. 

 Family II. EXOASCE.E. 

 Family III. GYMNOASCE^. 



With some systematic mixologists these species have not 

 been so definitely located. De Bary, '87, recognizing a mor- 

 phological relationship between them and the ascogenous 

 Saccharomycetes, unites both in an •' Exoascus Group" and 

 classifies them with his " Doubtful Ascomycetes." The struct- 

 ure and course of development of the Exoascac \^xy widely 

 from those of typical ascom3'cetes, and the acceptance of this 

 supposed phylogenetic atlinity requires the assumption that 

 they are forms in which by retrogression, all traces of archi- 

 carp and antheridial branch have been lost. A parallel case 

 is found in some species of Saproleg'uiie, oospores continuing 

 to be formed after antheridial branches have ceased. 



x\sci and spores are found in the Exoascccr, but although 

 there is an hymenium. there is no gathering together into a 

 distinct fructification with an investing membrane. Individual 

 asci are independent in the discharge of spores, which act is 

 continual and gradual, never simultaneous, hence the phenom- 

 enon of puffing, so common in other genera of the Discom}'- 

 cetes, is absent; it is probable the ejection takes place through 

 a minute apical opening. 



The cell wall of the spores is a simple hyaline membrane 

 incapable of being separated into exosporium and endosporium. 

 The germination of the spores is by sprouting, which in a 

 number of species takes place prior to their liberation from 

 the asci. Small bud-like germ-tubes sprout from any portion 



