CHYTRIDIALES 443 



fact that the latter were always arrested in their development led him 

 to suspect that Rhizophlyctis rosea was a parasite. Most of the above 

 finds record the species from cellulose substrata. This species is the 

 most widespread of all the Phycomycetes; it ranges from tropical land 

 masses to remote Pacific coral atolls, from temperate regions to the 

 Arctic. Its occurrence on such isolated atolls as Bikini, Rongerlap, and 

 the like suggests that it is wind-borne. 



Accounts of its development are given by Ward (1939) and Johanson 

 (1944). Haskins and Weston (1950) made a study of the factors influenc- 

 ing its pigmentation and growth. They find that the coloration, which 

 is probably due to carotenoid material, becomes more intense in well- 

 aerated cultures grown in the light, especially on media of high pH 

 value (6.8-7.0). Variations in type of development are given by Haskins 

 (1948). 



How many distinct species of chytrids have been ascribed to de Bary 

 and Woronin's species awaits a comprehensive study, made from single- 

 spore cultures, of all the pigmented forms of Rhizophlyctis. 



Rhizophlyctis spinosa (Karling), comb. nov. 



Karlingia spinosa Karling, Mycologia, 39: 60, figs. 23-33. 1947. 



Sporangium smooth-walled, spherical and 5-400 \l in diameter, 

 pyriform and 5-160 by 10-200 jx, oval and 4-70 by 7-100 \x, angular or 

 irregular, with one to eighteen exit papillae or tubes, 4-10 \l long by 

 3-7 [j. in diameter at base, the ends of which possess a hyaline glutinous 

 plug which may protrude 5-12 \x above apex, contents golden red; 

 rhizoids arising for the most part from several places on the sporangium, 

 main axes mostly coarse, attaining a diameter of 10 \x, much branched 

 and extensive; endooperculum hyaline, delicate, submerged in the 

 papilla or exit tube, shallowly convex, 8 \x in diameter, sometimes 

 sucked back into the sporangium; zoospores spherical or narrowly 

 ovoid, 3.3-4.4 \l in diameter with one to five (six?) golden-brown refrac- 

 tive globules, and flagellum 28-32 \x long; resting spore spherical and 

 6-22 [j. in diameter, oval and 8-12 by 10-15 \x, fusiform, elongate, 

 clavate, or narrowly rectangular and 5-8 by 12-17 \i, spiny to verrucose 

 with a golden-brown wall, contents coarsely granular bearing numerous 



