CHYTRWIALES 301 



? Rhizophydium decipiens (Braun) Fischer 

 Rabenhorst. Kryptogamen-FL, 1 (4): 100. 1892 



Chytridium decipiens Braun, Monatsber. Berlin Akad., 1855: 383; Abhandl. 



Berlin Akad., 1855: 54, pi. 5, figs. 1-4. 1856. 

 Phlyctidium decipiens (Braun) Cornu, Ann. Sci. Nat. Bot., V, 15: 121. 1872. 

 Olpidiella decipiens (Braun) Lagerheim, Journ. de Botanique, 2: 439. 1888. 

 Olpidinni (?) decipiens (Braun) H. E. Petersen, Bot. Tidsskrift., 29:423. 



fig. 25 f. 1909; Ann. Mycologici, 8: 555, fig. 25f. 1910. 



Sporangium within the oogonium of the alga but resting on the 

 surface of the ooplasm, spherical, subspherical, ovoid, or, if several 

 sporangia in a cell, occasionally somewhat irregularly tubular, variable 

 in size, up to 41 u. in diameter, wall smooth, colorless, thin or slightly 

 thickened, discharge tube broad, short-cylindrical or only slightly 

 elevated, its apex protruding through the oogonial pore; rhizoids not 

 observed; zoospores numerous, spherical or slightly elongate, 2.5-4 u, 

 in diameter, with a colorless, eccentric globule and a long flagellum, 

 movement hopping or amoeboid; resting spore lying in the oogo- 

 nium, apparently without rhizoids, ovoid or somewhat angular, rarely 

 spheroidal, 18-36 by 20 39 \l, wall very thick (2-6 jx), colorless, often 

 showing radial striations, contents evenly granular, without a large 

 globule, germination not observed. 



In oogonia of Oedogonium echinospermum, O. tumidulum, Braun 

 (loc. cit.), O. vaucherii, coll. Pringsheim, Braun (loc. cit.), Germany; 

 Oedogonium sp., Cornu (1872a: 121), France; Oedogonium sp., So- 

 rokin (1883:26, fig. 26), European Russia, Asiatic Russia; Oedo- 

 gonium sp., de Wildeman (1893b: 59, pi. 7, figs. 5-11), Belgium; 

 coll. Pittier, de Wildeman (loc. cit.), Costa Rica; Oedogonium sp., 

 Petersen (1909:423; 1910: 555, fig. 25f), Denmark; Oedogonium vau- 

 cherii, O. cardiacum, O. sexangulare, O. rufescens, Scherffel (1926a: 

 219, pi. 10, figs. 98-102), Hungary. 



It is debatable whether or not this is a species of Rhizophydium 

 (see remarks under Latrostium, p. 758). As Petersen (loc. cit.) points 

 out, no rhizoids have ever been found. Scherffel, however, who has 

 made the most critical study of it, emphasizes the fact, pointed out by 

 Braun, that the sporangium is "extramatrical" and rests on the egg 

 cell, which in turn is surrounded by the oogonial wall. He further states 



