92 MOLDS BELONGING TO THE PHYCOMYCETES 



the characteristic of the family already described in the key. See 

 Fig. 42. Cunninghamella (Chaenophoraceae) is a common air con- 

 taminant and is frequently isolated from soils. It has very tenuous 



TW. 42. Thamnidium : partly diagrammatic, showing terminal sporangium with 

 columella and numerous lateral sporangiola without columellae. 



rhizoids and forms clusters of unicellular conidia (sporangiola) on 

 the swollen end of a hypha. See Fig. 43. Syncephalastrum (Cepha- 

 lidaceae) is also occasionally encountered. In this several cells in 

 chains are found attached to a sporophore with a swollen tip. Each 



Fig. 43. Cunninghamella sp.: 1, most of the sporangiola removed from vesicular 

 enlargement of sporophore; 2, small cluster of sporangiola. 



chain is enclosed within a sporangial wall, but the appearance of the 

 spore head does not always reveal the endogenous character of the 

 spores. See Fig. 44. 



