468 AQUATIC PHYCOMYCETES 



Cladochytrium hyalinum Berdan 

 Amer. J. Bot., 28: 425, figs. 1-84. 1941 



"Thallus intra- and extramatrical, polycentric, eucarpic. Zoosporan- 

 gia imbedded in the substratum, or formed extramatrically, terminal or 

 intercalary, apophysate, proliferating, spherical, 15-40 u. in diameter, 

 subspherical, ovoid, pyriform, irregular, branched and lobed or greatly 

 elongated, 4-40 \i X 12-100 \i. Exit tubes commonly single, 2-6 u, x 

 2-10 u.. Rhizomycelium sparse or copious and extensive, richly branched 

 and anastomosed, 1.5-8 \x in diameter, with numerous round, oval, or 

 fusiform swellings, 2-10 \x : 4-14 u. (generally 4-10 \x x 6-10 u.). Zoo- 

 spores escaping in a globular mass, briefly quiescent previous to swim- 

 ming away, hyaline, spherical, 8-10 \x in diameter, uninucleate and poster- 

 iorly uniflagellate with a single highly refractive and extremely mobile 

 globule, 4-7 [i. in diameter; flagellum 40-50 \x long; method of swimming 

 rapid and darting. Resting spores usually spherical, 12-18 u, in diameter, 

 sometimes oval, pyriform or elongated (10-12 u. x 25-28 \x) and sub- 

 tended by several small, thin-walled cells; wall of resting spore smooth, 

 hyaline, several-layered; content including numerous hyaline, rounded, 

 refractive bodies, which later coalesce into a single, eccentric globule 

 about 8-10 [x in diameter. Resting spore functioning as a prosporangium 

 at germination, producing to the exterior, through a pore in its wall, a 

 hyaline, thin-walled zoosporangium similar to the evanescent one" 

 (Berdan, be. cit.). 



Saprophytic in grass leaves, Berdan (be. cit.), in rotting oak leaves, 

 Karling (1941b: 108), bleached grass leaves, Karling (1941a: 387; 

 1942c: 620; 1948c: 510), United States; cellophane, corn leaves, Shan- 

 or (1944: 332), Mexico; onion skin and corn leaves, Karling (1945a: 

 34), Brazil; grass, Haskins (1946: 135), Great Britain. 



The descriptions by Berdan and Karling 1 reveal no essential difference 

 between their two species other than slight variations in the extreme 

 values of size of parts and the presence of an endooperculum in Kar- 

 ling's fungus. A study by R. M. Johns (comm.) of a form similar to 

 Karling's Nowakowskiclla macrospora, save that no endooperculum is 



1 Of Nowakowskiella macrospora, Karling, p. 589. which was at first considered 

 identical with C. hyalinum. 



