1054 AQUATIC PHYCOMYCETES 



Mycelium delicate, profusely branched, with a silvery sheen, the 

 hyphae irregular, 2-8 \i in diameter, bearing budlike projections and 

 knotted complexes, endobiotic and extramatrical, contents with occa- 

 sional refractive granules ; zoosporangium borne on a slender unbranched 

 sporangiophore about 3 jx in diameter, ovoid or pyriform with a broad 

 blunt apex which may disappear just prior to zoospore discharge 

 26-48 u. long by 16-27 jo. in diameter, inner wall distinct, renewed by 

 internal proliferation, the secondarily formed sporangia up to five in 

 number, either sessile and "nested" within the primary sporangia or 

 formed in linear succession by repeated apical growth of the sporangio- 

 phore through the base of the sporangium; zoospores formed and 

 initiating movement within the sporangium, somewhat ovoid, 9-15 \i in 

 diameter, the flagella of about equal length, oppositely directed and 

 arising from a shallow groove, capable of repeated emergence, upon 

 germination forming one or more germ tubes ; oogonium formed on a 

 short branch, spherical, smooth-walled, 22-36 u, in diameter, antherid- 

 ium present on about ten per cent of the oogonia, diclinous, somewhat 

 clavate, broadly applied to the oogonium, the antheridial hypha winding 

 around the oogonium; oospore smooth, thick-walled, filling the oogo- 

 nium, contents highly refractive, finely granular, without a conspicuous 

 globule, upon germination forming one or more branched hyphae. 



Saprophytic on fruits and twigs, Petersen (he. cit.), Lund (1934: 47), 

 Denmark; (?) fruits and other plant parts, Minden (1916: 219, text fig. 

 24, pi. 6, figs. 45-48), Germany; Cejp (1933b: pi. 1, figs. 1-18, pi. 2), 

 Czechoslovakia; fruits, Kanouse (loc. cit.), Fraxinus twigs, Sparrow 

 (1933c: 533), United States; Barnes and Melville (1932), twigs, 

 Sparrow (1936a: 467), (?) Forbes (1935a: pi. 9, fig. 7), Great Britain; 

 fruits, Crooks (1937: 220, fig. 6 A-E), Australia. 



The description above was derived for the most part from Kanouse's 

 (1925) account of her fungus. The fungi described by Cejp (op. cit.) and 

 Crooks (op. cit.) most nearly approximate it, particularly with respect 

 to the sex organs and the oospore. The sporangia of the Australian 

 material were, however, somewhat larger, being 40-70 by 20-40 \x. The 

 oogonia were 23-28 \x in diameter, and the oospores, which lacked a 

 globule and filled the oogonium, were 20-22 \x in diameter. It is possible 

 that larger sporangia were also formed in the material described by Cejp. 



