166 THE FUNGI WHICH CAUSE PLANT DISEASE 



families are monogeneric; the third on hoofs, horn, etc.; the 

 sixth is subterranean and the Terfeziaceae more or less subter- 

 ranean. 



Aspergillacese (p. 165) 



The ascocarp, in many forms but rarely seen, is a small spherical 

 or tuber-shaped body, usually indehiscent, rarely opening by a 

 pore; The spherical or pyrif orm asci bear from 2 to 8 spores which 

 may be from 1 to many-celled. The ascocarp is in some genera 

 provided with appendages which strongly resemble these of 

 the Erysiphaceae (Microascus). Conidia are produced in great 

 abundance. 



In Aspergillus and Penicillium fertilization is said by some 

 observers to be accomplished by conjugation of a straight oogo- 

 nium with a spirally coiled antheridium, this act resulting in an 

 ascogenous hypha. Recent work of Dale '" (see also Fraser and 

 Chambers ^^) denies such fusion in one species of Aspergillus 

 which she studied, though sexual organs were often present, 

 and predicates a reduced form of sexuality consisting of fusion 

 of the nuclei of the ascogonium with each other. 



Key to Genera of Aspergillaceae 



Spores 1-celled 

 Perithecium flask-shaped, beaked or papil- 

 late 1. Microascus. 



Perithecium not beaked 



Perithecium with hair-like appendages; 

 peridium compact, mostly dark 

 colored 

 Appendages straight hairs or forming 



a hairy felt 2. Cephalotheca. 



Appendages apically coiled hairs. ... 3. Magnusia. 

 Perithecium imappendaged; peridium 

 membranous or fleshy 

 Conidia borne directly on the myce- 

 lium 

 Chlamydospores borne in chains. . 4. Thielavia, p. 167. 

 Chlamydospores borne singly 5. Rostrella, p. 168. 



