330 CLASS ASCOMYCETEAE 



In 1903 Miss Dale observed the passage into the ascogonium of several 

 male nuclei. The ascogonium divides into a number of cells each of which 

 produces ascogenous hyphae. The perithecial wall in this genus is a mass 

 of loosely interwoven hyphae with spines and prongs. Hotson (1936) ob- 

 served similar reproductive structures in Arachniotus trisporus Hots., as 

 did DeLamater (1937) in a species close to A. aureus (Eidam) Schrot. The 

 latter demonstrated the passage of a nucleus from the antherid into the 

 ascogonium coiled about it. The nuclei then multiply by conjugate divi- 

 sion and the ascogonium divides into binucleate cells from each of which 

 a crozier buds out to give rise to an ascus. The uninucleate tip and basal 

 cells of the crozier often unite and produce another crozier. Nuclear fusion 

 occurs in the young asci and eight ascospores are formed. Fifty single- 

 spore cultures were made and all were fertile showing that this species is 

 self-compatible. (Fig. 106 B-D.) 



Family Elaphomycetaceae. These fungi are subterranean and prob- 

 ably saprophytic although possibly they may produce mycorrhiza. The 

 ascocarps are large, up to 2 or 3 cm. in diameter with a very thick perid- 

 ium, usually hard and roughened externally, the central portion consisting 

 of the ascogenous hyphae and asci and the thin-walled central cells of the 

 ascocarp, traversed radially by the "veins" which probably are conduc- 

 tors of foodstuffs. The cell walls of the central portion dissolve leaving the 

 numerous ascospores free in the center of the ascocarp. Clemencet (1932) 

 reported that in Elaphomyces no sexual organs are to be found but that in 

 Ascoscleroderma (a segregate of that genus) a stout ascogonial filament 

 coils around a straight antherid which however is sexually functionless. 

 From the ascogonium arise branching ascogenous hyphae which produce 

 at their tips rectascous asci, i.e., the cell elongates and the nuclei fuse 

 without any curving or hook formation. In Elaphomyces on the contrary 

 the asci are subterminal and, judging by the illustrations, are formed by 

 means of croziers. C. W. Dodge (1929) recognized 24 species of Elapho- 

 myces, mainly from Central and Southern Europe and the United States. 

 One species is reported from Italy, France, and Australia. 



Family Onygenaceae. This family contains a few species in the 

 single genus Onygena, found mostly in temperate Europe and North 

 America. They grow on old feathers, hair, hoofs, horn, felt, and other 

 animal matter. The ascocarps are a few millimeters up to 1 or 2 cm. tall, 

 consisting of a stalk and a somewhat enlarged head within which the asci 

 are scattered in the manner characteristic of this order. The tissues break 

 up into a sort of capillitium. (Fig. 107.) 



Family Trichocomaceae. In this family consisting of the one genus 

 Trichocoma, and only a few species, the ascocarp is sessile. When young 

 it is closed with a firm peridium which is thinner above. The ascogenous 

 portion develops centrally and consists of irregularly scattered asci with 



