CHYTRIDIALES 161 



Sporangia one to four in the swollen host cells, spherical, 30-80 u, 

 in diameter, with one or two discharge tubes 20-40 u. in length which 

 just pierce the host wall but do not extend beyond it; zoospores ini- 

 tiating movement within the sporangium, escaping singly to the out- 

 side, ellipsoidal, 5 \j. long by 3 ;x broad with a lateral refractive globule 

 and a single, laterally attached and posteriorly directed flagellum; 

 resting spore not observed. 



Parasitic in and causing hypertrophy of moss rhizoids, Petersen 

 (loc. cit.), Denmark; Funaria hygrometrica, coll. W. Tutin, Ingold 

 (Joe. cit.). Great Britain. 



The description is compiled from the papers of Petersen and Ingold. 



Although the sporangia exhibited by Ingold's material possessed 

 only one discharge tube, he is probably correct in assigning his fungus 

 to Petersen's incompletely known species. 



Pleotrachelus petersenii Lund 

 Bot. Tidsskrift, 41 : 241, fig. 1. 1930 



Sporangium broadly oblong-cylindrical, straight or curved, 24-89 [i 

 long by 9-28 u. in diameter, wall thin, smooth, colorless, with from one 

 to six very narrow discharge tubes 5-1 1 \x (up to 25 u,) long; zoospores 

 uniflagellate; resting spore not observed. (Modified from Lund.) 



In Oedogonium sp., Denmark (S.). 



A fungus with more tubular sporangia bearing inflated contorted 

 branches has been tentatively identified with this species by Sparrow 

 (1936a: 428, pi. 14, fig. 5). No zoospores were seen, and hence no 

 positive identification could be made. 



IMPERFECTLY KNOWN SPECIES OF PLEOTRACHELUS 



? Pleotrachelus inhabilis H. E. Petersen 



Oversigt. Kgl. Danske Vidensk. Selskabs. Forhandl., 1905 (5): 456, 



fig. IV, 1-6 



A collective species containing Pleotrachelus-Y\kc forms found in 

 Polysiphonia violacea and Polysiphonia elongata. 

 Two main types of sporangia occur: (1) those in tetrasporang'a and 



