CHYTRIDIALES 535 



? Chytridium xylophilum Cornu 



Ann. Sci. Nat. Bot., V. 15: 116. 1872 



Rhizidium xylophilum (Cornu) Dangeard, Le Botaniste, 1:64. 1889. 

 Rhizophydium xylophilum (Cornu) Fischer, Rabenhorst. Kryptogamen-Fl., 

 1 (4): 98. 1892. 



Sporangia resting on the surface of the fibers, often in long rows, 

 ovoid, acuminate, flattened, with or without a long tube which termi- 

 nates in a papilla; rhizoids not observed; zoospores spherical, with an 

 eccentric globule and a single flagellum, method of escape not described; 

 resting spore free (?), spherical, with a moderately thick smooth wall 

 and a large pale-brown oil globule. 



Saprophytic on submerged decaying fibers of Corylus avellana, Tilia, 

 hemp, France. 



Both Dangeard (1886a: 300, pi. 13, figs. 6-9) and Scherffel( 1926a: 247, 

 pi. 11, figs. 144-146) have referred fungi to Cornu's incompletely known 

 species. Dangeard's chytrid rested on "fibres" and had an ovoid spo- 

 rangium with a prominent apical papilla. Sporangia were also found 

 within the tissue, where they underwent deformation. Since the zoo- 

 spores upon germination in water produced rhizoids they were probably 

 present on the natural substratum, though unobserved. Discharge 

 presumably was inoperculate, the zoospores clustering in a rounded 

 motionless mass from which they soon escaped. Scherffel's fungus 

 formed sporangia on the fibers of decayed Typha or in the cells. When 

 free some assumed an irregular broadly pyriform shape, generally with 

 a somewhat laterally placed prominent papilla bearing an operculum. 

 Others were spheroidal with a slightly elevated papilla, or broadly ovoid 

 with a somewhat lateral tapering discharge tube. They varied in size, 

 being 20-36 u. in diameter by 16-34 \l high. The zoospores were spher- 

 ical, 8 [x in diameter. No rhizoids were observed. Scherffel's fungus 

 differed from both Cornu's and Dangeard's in having operculate spo- 

 rangia. All these fungi have been incompletely observed, and since the 

 rhizoidal system of Cornu's plant was not found it seems useless to at- 

 tempt an interpretation of his species. 



Sparrow (1936a: 432, pi. 15, figs. 21-26) described an operculate 

 fungus with pyriform or irregular sporangia imbedded in the spongy 

 woody tissue of submerged Aesculus and Quercus twigs in England and 



