900 AQUATIC PHYCOMYCETES 



fruits and twigs, Minden (1915 : 599; 1916 : 188, pi. 3, fig. 21 ), Germany ; 

 Cejp (1932b: l,pl. 1, figs. 1-5, pi. 2, figs. 1-3), Czechoslovakia; apples, 

 twigs of Alnus, Lund (1934: 37, fig. 17 a-b), Denmark; rose fruits, 

 Forbes (1935a: 235, fig. 2; 1935b: 3), twigs of Quercus, Sparrow (1936a: 

 460, pi. 20, fig. 2), (?) tomato fruits, Waterhouse (1942: 321), crabapple, 

 Great Britain; Beverwijk (1948:245, fig. 8), Holland; fruits of 

 Macrocarpium officinale, Indoh (1953: 33, figs. 19-21), Japan. 



The record of Crooks (1937: 218, pi. 10, fig. 5) from Australia is open 

 to question, since no sex organs were observed. This species cannot be 

 distinguished from Rhipidium interruption except in the sexual stage. 



The isolation and cultivation of this species is recorded by Emerson 

 (1950). 



Rhipidium parthenosporum Kanouse 

 Amer. J. Bot., 14: 344, pi. 48, figs. 34-37. 1927 



Basal cell slender and elongate, once or twice forked, 800-1000 y. long 

 by 25-30 [x wide, wall smooth, colorless, 7-10 \i thick, branches very 

 short, ellipsoid or globose, umbellate, constricted at the point of 

 origin and beneath the reproductive organs, constrictions with cellulin 

 deposits, holdfasts few; sporangia ellipsoidal, thin-walled, 32-60 [x long 

 by 25-50 u. wide, borne in umbellate clusters on short branches; zoo- 

 spores not observed; antheridia lacking; oogonia spherical, thin-walled, 

 52-54 (J. in diameter, pedicellate, borne in umbellate clusters on the 

 short branches, the contents during development differentiated into 

 ooplasm and periplasm, the latter with strongly marked radiating 

 periplasmic strands and appearing cellular; mature parthenospore not 

 observed. (Modified from Kanouse.) 



In dense mats or loose tufts. On apple, Kanouse (Joe. cit.), United 

 States; apples, Lund (1934:38, fig. 17c), Denmark; twigs, Sparrow 

 (1936a: 460), Great Britain. 



Sparrow (he. cit.) observed that spherical smooth somewhat thick- 

 walled bodies formed in and completely filled the oogonia. These may 

 be the mature parthenospores. 



