no THE SAPROLEGNIACEAE 



5. Achlya cornuta Archer. Quart. Jour. Mic. Sci. 7: 126, pi. 6, figs. 

 2-6. 1867. 

 ? Achlya stellata deBary. Bot. Zeit. 46: 648, pi. 10, figs. 10 and 



II. 1888. 

 This species has been found by Humphrey at Amherst and this is 

 the only American record. His description follows ('92, p. 126. See also 

 his pi. 20, figs. 103 and 104): 



"Hyphae of medium size, short. Zoosporangia rare, cylindric. 

 Oogonial branches rarely long, straight or flexuous, racemosely arranged. 

 Oogonia terminal, globular or elliptical, densely beset with rather long, 

 blunt outgrowths of their unpitted walls, the apical one often larger 

 and forming an evident apiculus. Antheridial branches and antheridia 

 wanting. Oospores from one to four in an oogonium, globular or slightly 

 flattened, centric, their average diameter about 2910.. 



" Massachusetts — Amherst. Europe. 



"The same culture which yielded A. megasperma for the first time 

 contained a small amount, all I have seen, of this form. It has been 

 referred with some doubt to Archer's species, since it fails to show at 

 all a feature which one would suppose, from that author's account and 

 figures, to be very characteristic of his plant; namely, the development 

 of several oogonia in a series from a single hypha. In other respects, 

 however, it corresponds too closely with his description to justify one 

 in regarding it as distinct. Archer saw no sporangia, probably not, 

 as he thought, because he found it too late, but because of their rarity. 

 In species which 'produce sporangia abundantly, one can always find 

 empty ones on plants with mature oospores. \n the limited material 

 at my disposal, I have been able tO; find but a single one, and that only 

 long after it was emptied. Frorrt below its; base, arose a branch bearing 

 an oogonium. This, so far as it goes, supports Archer's conclusion that 

 the plant is an Achlya, which seems almost certainly correct. The 

 oogonial branches sometimes show the incurving mentioned by Archer, 

 and are often less definitely bent. This writer states that an oogonium 

 may contain as many as eight or ten oospores; but I have never seen 

 more than four, and his figures show no more than three. He describes 

 no special antheridial branches, but says that the antheridia are like 

 those of A. dioica Pringsh. As these latter are not antheridia at all, 

 one would expect to find, as is the case with American specimens, that 

 the species has no true male organs. As will be seen from the figures, 

 the spines could hardly be more closely set, and their form is more cylin- 

 drical than conical. 



"This and the next species [A. stellata deBary] seem to be closely 

 related, the more so if the American form here described proves to be 

 more typical than Archer's." 



