Fungous Flora of the Soil 443 



Obligate saprophytes 

 Species of Phycomycetes 



Mucorales 



Rep/oduction asexually by spores contained in sporangia . . Sporangiophorae 



Reproduction asexually by conidia produced either solitary or in 



chains Conidiophorae 



Suborder Sporangiophorae 



I. Sporangia generally only of one kind, spherical or pyriform, with a 

 membrane that dissolves or fractures easily. Sporangioles with persistent 

 membranes occur very rarely and in such cases are disposed without 

 order along the principal sporangiophore. The septum separating the 

 sporangiophore from the sporangium arches in the interior of the latter 

 to form a columella. Zygospores naked or surrounded by appendages 

 Mucoraceae 



II. Sporangia as with the Mucoraceae but of two kinds: the one 

 multispored, with membrane that dissolves, leaving only a naked 

 columella; the other (sporangioles) few-spored, with persistent membrane, 

 often without columella, caducous. The sporangioles are disposed at the 

 extremity of branched sporangiophores, which are fixed at regular intervals 

 on the principal sporangiophore Thamnidiaceae 



III. Sporangia of one kind only, multispored, with membrane for the 

 major part solid, persistent, of a very dark blackish color, or swelling only 

 toward the base. Sometimes the sporangium dissolves, leaving the 

 columella, while at other times it is thrown off at the same time as the 

 columella and opens only after swelling of the membrane .... Piloholaceae 



IV. Sporangia without a columella, with diffluent evanescent membrane. 

 Zygospores contained singly in a completely closed carpospo- 

 rium Mortierellaceae 



Family Mucoraceae 



1. Sporangia pyriform Ahsidia 



Sporangiag lobose 2 



2. Sporangiophores fasciculate on a rhizoidiferous stolon, located on the 

 nodes opposite the rhizoids; spores often striated longitudi- 

 nally Rhizopus 



Sporangiophores emerging solitary from the mycelium, no rhizoidiferous 

 stolons; spores generally smooth without longitudinal striations 3 



3. Heterothallic, occasionally homothallic, but in this case the zygophores 

 generally arise from comparatively distant parts of the mycelium, never 

 formed between branches of a single aerial hypha, usually equal . . Mucor 



