ASCOMYCETES 

 Order 5. LABOULBENIALES 



Thaxter 197, 2:220; Lindau 491 



Receptacle consisting of two to many cells in a row, or parenchyma-like, regu- 

 larly producing from the cells one or more appendages bearing antherids as a rule; 

 antherozoids normally endogenous, borne within flask-like, simple or compound 

 antherids, rarely produced like conidia, i. e., naked or exogenous; perithecia one to 

 many, stalked or sessile, terminal or lateral on the receptacle, resulting from fer- 

 tilization by means of a trichogyne; asci seriate, mostly 4-spored; spores usually 

 2-celled. 



This key is merely compiled from those constructed by Thaxter in his first 

 two monographs (1895, 1908) and is fully subject to the statement made in the 

 second (p. 236); "It is not expected that this key will prove useful as a means of 

 determining genera to anyone who has not made himself familiar with the general 

 conditions existing in the group and summarized in the preliminary matter of this 

 and the preceding Monograph." Since this order rests almost wholly upon the 

 monumental researches of Thaxter, those who wish to become in any degree familiar 

 with it must turn to the several monographs (cf. bibliography). These render it 

 unnecessary to attempt to include here the genera published since 1908, a complete 

 key to the order as at present constituted being impossible for anyone but the 

 master of the group himself. 



Key to Families 



A. Antherids specially diflferentiated cells or groups 



of cells 



1. Antherids compound, the antheridial cells en- 



dogenous, arising from one or more inter- 

 calary cells and discharging into and from a 

 common chamber (eventually free in a com- 

 pact group in Distichomyces) Peyritschiellaceae p. 42 



2. Antherids single cells with free efferent tubes Laboulbeniaceae p. 44 



B. Antherids more or less undifferentiated cells of 



the appendages or their branches Ceratomycetaceae p. 45 



Family 12. PEYRITSCHIELLACEAE 



A, Dioecious 



1. Perithecia and appendages in pairs to the right 



and left 



2. Perithecia and appendages in a row 



B. Monoecious 



1, Antherids arising on an appendage 

 a. Antherids lateral 



(1) On a subbasal cell of the appendage 



Dimorphomyces T 264, 2:240; 



L 497 

 Dimeromyces T 267, 2:241; 



L 497 



Cantharomyces T 271, 2:281; 

 L 497 



42 



