108 THE FUNGI IMPERFECTI AND THE ASCOMYCETES 



number of species is known, mostly saprophytes, but at least one is 

 known to be a plant pathogen and one, Sporotrichum Schenckii, is the 



cause of an important mycosis, sporo- 

 trichosis. See page 193. 



Verticillium. In this genus the erect 

 conidiophores are septate and branched. 

 They are arranged in whorls and 

 these branches rebranch also in whorls. 

 From these numerous tips, whorls of 

 round, elliptical, oval, or short spindle- 

 shaped conidia are borne. Either co- 

 nidia or mycelium or both may be 

 hyaline or they may be slightly pig- 

 mented. 



Trichoderma. Not infrequently one 

 finds growing on plate cultures a mold 

 which is of a very bright pure green color; the aerial mycelium 

 is very abundant, and frequently little tufts of white (sterile) 

 aerial mycelium project above the conidiophores. Microscopic ex- 



FiG. 57. Sporotrichum 



Schenckii from stained slide 



culture. 



Fig. 58. Verticillium sp.: 

 a, conidiophores in 

 whorls; b and c, conidia 

 attached to conidio- 

 phores; d, conidia. From 

 Conant et al., Manual of 

 Clinical Mycology, 1944. 



oo 

 d a 



Fig. 59. Trichoderma: a, 

 mycelium; b, conidio- 

 phores; c, cluster of co- 

 nidia; d, conidia. From 

 Conant et at., Manual of 

 Clinical Mycology, 1944. 



amination reveals numerous small clusters of conidia attached di- 

 rectly to the tips of the many-branched conidiophores (Fig. 59). 



This is Trichoderma viride, one of the most numerous of the soil 

 fungi, and a very common contaminant in bacteriological work. It 



