34 



SPIROGYRALES 



Subfamily Cladochytriae 



Mycelium wide-spreading, developing terminal and intercalary enlargements, 

 transformed wholly or partly into sporangia or resting spores; genera for the most 

 part poorly defined. 



A. Zoospores amoeboid, not ciliate; on Chaetophora Amoebochytrium 101 



B. Zoospores ciliate, not amoeboid 



1. Sporangia present, terminal or intercalary, 



formed from enlargements of the mycelium; 

 resting spores rare or absent 



a. Sporangia with a lid, proliferating 



b. Sporangia without a lid, not proliferating 



(1) Mycelium of rather broad cylindric 



threads; sporangia developed from fusi- 

 form swellings and separated by short 

 cylindric cells 



(2) Mycelium of extremely delicate ramose 



threads; swellings globose or irregular Cladochytrium 102 



2. Sporangia rare, when present epibiotic and de- 



veloping directly from the zoospore; resting 



spores present and abundant Physoderma 103; 1 



Nowakowskiella 101 



Catenaria 101 



Order 2. SPIROGYRALES 



Typically 1-celled or filamentous yellow-green algae without zoospores; sexual 

 reproduction by the conjugation of non-motile usually equal gametes; four fungous 

 families. 



Key to Families 



A. Fructification by means of sporangia and zygo- 



spores or one of the two 



1. Conidia endogenous in globoid to cylindric 



sporangia, rarely exogenous 



2. Conidia exogenous, single on clavate conidio- 



phores; largely entomophilous 



3. Conidia exogenous on cylindric conidiophores 



and endogenous in elongate sporangia 



B. Fructification by means of a definite sporo- 



carp containing zygospores, azygospores or 

 sporangia 



Mucoraceae p. 34 

 Empusaceae p. 37 

 Ascoideaceae p. 37 



Endogonaceae p. 36 



Family 4. MUCORACEAE 

 Schroeter 119; Fitzpatrick 234 

 Saprophytes, rarely parasites, with a well-developed branching mycelium in 

 which septa are lacking; propagation by spores (conidia) arising within sporangia, 

 the latter apparently reduced to chains of conidia in one subfamily; reproduction 

 by the fusion of the end-cells or gametes of conjugating tubes; zygospores naked 

 or surrounded by filaments or a weft of hyphae. 



Key to Subfamilies 

 A. Sporangia present 

 1. Columella present 



a. Wall of sporangium uniform, not cutinizcd, 

 diffluent 



(1) Sporangioles or conidia present Choanophorae p. 



(2) Sporangioles and conidia lacking as a rule Mucorae p. 



