SAPROLEGNIALES 845 



then emerging as biflagellate spores; sexual reproduction by means of 

 oogonia containing one egg; antheridia not observed. (Modified from 

 Coker and Matthews, 1937.) 



Type species: Sommerstorffia spinosa Arnaudow. 



Prowse (1954a) describes smooth-walled oogonia with one to seven 

 eggs and an antheridial system composed of four branches closely 

 applied to the oogonial wall. Since only one such instance was observed, 

 he feels that abnormal material may be involved. Even if the material 

 was normal, this fungus is certainly not Sommerstorffia spinosa. Karling 

 (1952) gives a brief account of another possible species which lacks 

 specialized capturing organs and adheres to the substratum by a basal 

 flattened holdfast. 



PLECTOSPIRA Drechsler 



J. Agr. Res., 34: 294. 1927 



(Fig. 66 C, p. 842) 



"Mycelium slender, sparingly or moderately branched. Zoosporangia 

 composed of inflated elements, often compacted into an irregular com- 

 plex, within which zoospores are differentiated in two or more series, 

 together with a prolonged filamentous element within which zoospores 

 are formed in one series and by which the entire organ is evacuated. 

 Zoospores encysting at the mouth of the efferent hypha, later escaping 

 from their cysts and swarming. Oogonia intercalary or terminal. Anther- 

 idia absent or present. Oospores single and somewhat eccentric (sub- 

 centric) in internal structure" (Drechsler, loc. cit.). 



Type species: Plectospira myriandra Drechsler. 



A genus whose undoubted members have thus far only been reported 

 as root parasites of flowering plants. Whether or not Plectospira dubia 

 Atkins (1954b), parasitic on various Crustacea, belongs here is, as its 

 author indicates, questionable. 



TAXON NOT IN COKER (1923) OR COKER AND MATTHEWS (1937) 



Plectospira dubia Atkins 

 J. Mar. Biol. Ass. U.K., 33: 731, figs. 1-5. 1954 

 See Sirolpidium zoophthorum, p. 968. 



