SOIL FUNGI 255 



2'. Spores two-celled, conidia solitary: 



(a) Conidia with both cells smooth: 



(a') Conidia born on sides of conidiophores 

 usually on inflated cells, not terminal, 

 Arthobotrys. Rarely found in the soil. 



(b') Conidia produced at tips of conidiophores, 

 not lateral, conidia solitary or in heads, 

 pear shaped, Trichothecium. Isolated fre- 

 quently from the soil. 



(b) Terminal cell of conidium enlarged and roughened, 



Mycogone. Isolated frequently from the soil. 

 2. Vegetative hyphae either short, almost unnoticeable, often 

 breaking up into spores, or as abundant moldy growth, 

 septated, usually dark, seldom light colored (with dark 

 spores). Conidiophores short, upright, simple or branched, 

 dark colored. Conidia unseptated or variously septated, 

 always dark colored, light only in exceptional cases (the my- 

 celium and conidiophores are then dark). Dematiaceae. 

 1'. Conidia unicellular: 



1". Mycelium little developed and breaking up into 

 oidia, or conidia formed on short lateral hyphae 

 that are not well differentiated from the remainder 

 of the mycelium; conidia in chains easily broken 

 up, Torula. Various species of Torula were 

 found in the soil by Koning, Dale, Pratt and 

 others. 

 2". Mycelium definitely developed, with well differen- 

 tiated conidiophores: 



(a) Conidia not in chains: 



(a') Conidia in terminal heads: 



(a") Conidia developing directly 

 from conidiophore or with 

 very short sterigmata, Syn- 

 sporium. Isolated from the 

 soil by Dale, 

 (b") Conidia on thick, long sterig- 

 mata, Stachybolrys. Two 

 species isolated from the 

 soil by Jensen, 

 (b') Conidia not in terminal heads ; conidia 

 prickly, Zygodesmus. Isolated from 

 the soil only rarely, 

 (c') Single conidia produced on branches, 

 irregularly produced on the sides 

 of the mycelium, Acremoniella. 

 Rarely found in the soil. 



(b) Conidia in chains: 



(a') Conidiophores unbranched, lateral, 

 with terminal chain of spores, Dema- 



