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246 BOTANICAL GAZETTE [April 



with the lack of detail in many of these figures, which has led me 

 to think that Trow may have made a number of mistakes which 

 would quite invalidate his evidence in support of sexuality. Figs. 

 4j^ 44, and 46, labeled ''female gameto-nuclei/' give appearances 

 which are very similar to coenocentra, and I fear that he was 

 not able to separate these structures in his preparations. Fig- 3 5 

 certainly indicates that his material had coenocentra. But the 

 most serious difficulties are encountered in his drawings of male 

 gameto-nuclei [figs. 45, 46), These are not clear enough to be 

 convincing; indeed, they seem to the writer to be the remains 

 of degenerating nuclei at the periphery of the ^gg- Side by side 

 with the structures labeled '*male gameto-nuclei" Trow figures 

 bodies, very similar in appearance, which are probably degener- 

 ate nuclei. In the face of this uncertainty and seeming contra- 

 diction of evidence the illustration of an antheridial filament 

 piercing the egg (Trow, iSgg, Jig. 45) loses much of its weight, 

 and the statement that two nuclei fuse in the center of the egg 

 (Trow, 1899,7?^. 47) is open to much doubt. The subject is so 

 difficult that there are abundant opportunities for error, and we 

 are justified in asking for much more evidence before accepting 

 such important conclusions. 



The writer cannot better sum up his attitude toward Trow's 

 opinions on sexuality in the Saprolegniales than by defining 

 them as ?iot proven and improbable in the face of the mass of 

 observations upon which botanists have generally agreed that 

 the group is apogamous. The view of apogamy formerly 

 resting entirely on the failure to find antheridial tubes fusing 

 with the eggs is now supported by the present investigation on 

 the details of oogenesis. These show that the binucleate egg, 

 formerly difficult to understand on the theory of apogamy, may 

 arise very naturally In a multinucleate oogonium when the method 

 of oogenesis is as just described for Saproleg?iia mixta. 



The binucleate and trinucleate eggs of Saprolegnia are essen- 

 tially similar to the multinucleate eggs of Albiigo Bliti and 

 A, Portiilacae, and the conditions in the young eggs of A. 

 Candida and A. Tragopogonis, as described by Stevens (1899- 

 1901). The latter, it will be remembered, contain several 



