AN ACHLYA LACKING SEXUAL REPRODUCTION 363 
this paper differs from A. oidiifera and A. paradoxa in the distinct 
morphological character of its resistant spores and in the absolute lack 
so far of any sexual reproduction. The destruction of stock cultures 
has prevented testing the effect of mixtures of leucin and levulose in 
the proportions found successful by Pieters (15) in inducing oogonium 
formation in Saprolegnia. It is possible that this Achlya also would 
yield to this combination or to some other more suited to its own 
physiologic idiosyncrasies. In view of such a possibility it does not 
seem advisable to assign a specific rank and name to the Achlya de- 
scribed above. Both physiologically and morphologically this Achlya 
differs from the other members of the genus; but further investigation 
might result in inducing the formation of sex organs, and might prove 
the fungus to be a variety of some already established species. 
The significance of these Saprolegniaceous forms which partially 
or completely lack sexual reproduction is not at once apparent. The 
few explanatory theories advanced by early investigators were based 
on the study of material under unfavorable conditions preceding 
methods of pure culture; and hence may be disregarded. Even the 
more modern investigators of such forms offer but little explanation 
of their significance. Maurizio's theory that asexual resistant spores 
(Sporangienanlage) are reminiscent of primitive, non-specialized 
structures from which both sporangia and oogonia have been evolved 
has been largely nullified by Klebs' exact researches on "gemma" 
formation. On the other hand, in Klebs' interpretation of ''gemmae" 
as " Hemmungsbildungen " induced by conditions unfavorable to 
other stages of development, we have an explanation undoubtedly 
correct in most cases, yet hardly applicable to such distinct and con- 
sistently formed structures as the resistant spores of the Achlya that 
is the subject of this paper. 
An extremely significant suggestion, however, has been made by 
Pieters in a recent paper. Pieters' (15, p. 483) suggestion that "the 
production of sexual organs may depend on some special combination 
of conditions, differing, doubtless, for each form" is important in 
emphasizing the physiological difference existing among the species 
and varieties of the Saprolegniaceae. The members of the family, 
probably because they are coenocytic in structure, and are completely 
submerged in the culture media, are very sensitive to the nature of 
their environment. Morphologic studies reveal no reason why under 
the same conditions one form should produce oogonia and antheridia; 
