254 PRINCIPLES OF SOIL MICROBIOLOGY 



2'". Conidiophores unbranched or branched, but 

 branches and conidia not forming a terminal 

 head: 



V" . Conidia born on simple or branched, but not 

 whorled hyphae: 



(a) Conidia produced irregularly on the myce- 

 lium, or on short lateral branches, Sporo- 

 trichum (No. 97, PI. XIV). Commonly found 

 in the soil, but insufficiently studied. 



(b) Conidia produced on definitely differentiated 

 erect conidiophores, which are usually much 

 branched: 



(a') Conidia single, terminal, Monosporium. 



Isolated from the soil by Koning, Dale and 



others, 

 (b') Conidia are usually loosely grouped at tip, 



Botrytis (No. 109, PI. XIV). Represented in 



the soil by a number of species, some of which 



(B. cinerea) are cosmopolitan. 

 2"" . Conidiophores branched in whorls: 



(a) Conidia-bearing branches thick and flask- 

 shaped; conidiophores with long sterile tips, 

 Pachybasium. Isolated from the soil by 

 Goddard. 



(b) Conidiophores without sterile tip, conidia not 

 produced on flask-shaped branches: 



(a') Conidia not forming chains: 



(a") Conidia not embedded in slime, Verticillium. 

 Represented in the soil by various species, 

 some of which possess a strong cellulose de- 

 composing power. Species of Geomyces, 

 related to Verticillium, have been isolated 

 from the soil by Traaen. 



(b") Conidia embedded in slime, Acrostalagmvs 

 (No. 98, PI. XIV). Frequently found in the 

 soil. 



(1)') Conidia in terminal chains, Spicaria. Vari- 

 ous species of this genus were isolated from 

 the soil. 

 3". Conidia born on differentiated intercalary cells of 



the conidiophore: 



(a) Cells, bearing conidia, with raised points for 



attachment of conidia, Gonatobotrys. 

 Rarely found in the soil. 



(b) Cells, bearing conidia, smooth, Nemato- 



gonium. Isolated from the soil by Koning 

 and Dale. 



