256 PRINCIPLES OF SOIL MICROBIOLOGY 



Hum (No. 110, PL XIV). Fre- 

 quently found in the soil, 

 (b') Conidiophores with branched chains 

 of conidia, Cladosporium (Hormo- 

 dcndrum). Common in the soil, 

 various species having been isolated 

 by a number of investigators (No. 

 100, PI XIV). 

 2'. Conidia two-celled: 



(a) Conidiophores short, not well differentiated from 

 the mycelium: 

 (a') Conidia solitary, Dicoccum. Rarely found 



in the soil, 

 (b') Conidia in chains, Dispora. Rarely found 

 in the soil. 

 3'. Conidia more than two-celled: 



(a) Septa of conidia perpendicular to long axis of 



spore, all parallel; conidia not in chains, Hel- 

 minthosporium,. Frequently found in the soil. 



(b) Septa of conidia both longitudinal and crosswise; 



conidiophores well differentiated: 

 (a') Conidia solitary and apical: 



(a") Conidiophores decumbent, formed 

 in lateral branches of mycelium, 

 Stemphylium. Various species 

 have been isolated from the soil, 

 (b") Conidiophores straight, more erect, 

 conidium terminal, Macros porium. 

 Found in the soil by Dale and 

 Pratt, 

 (b') Conidia in chains, Alternaria (No. 107, PI. 

 XIV). Represented in the soil by sev- 

 eral species. 

 3. Vegetative hyphae mostly invisible, septated, branched, 

 hyaline or dark colored. Conidiophores uniting in parallel 

 strands to form upright coremia. From the separation of 

 hyphae, at the top of the coremium, the conidiophores either 

 form a head or are slightly radiating, Stilbaceae: 

 1'. Hyphae, coremium, and conidia hyaline or light colored; 

 conidia one-celled; coremium with a more or less defi- 

 nite head, conidia not born along entire side: 



(a) Conidiophores scarcely diverging at top, Ciliciopo- 



dium. Rarely found in the soil. 



(b) Conidiophores divergent at top; each coremium 



with lateral heads as well as terminal, Tilachli- 

 dium. Found in the soil by Koning. 

 2'. Hyphae, coremium and conidia usually all dark: 



(a) Conidia not in chains, ovoid to oblong, hyaline, 

 Graphium. Rarely found in the soil. 



