APLAXES 77 



any other genus. It is also obvious that these species arc related to 

 Saprolcguia hypoiiymi and it may in the end lie best to transfer it also to 

 A planes. However, as its sporangia and spores are well known to be of the 

 Saprolegnia type and behavior, so that it may be retained in that genus 

 without violence, we think it best to let it alone for the present at least. 

 Saprolegnia Utoralis is a connecting link with the Ferax group. 



As modified to include 5. Treleaseana the genus Aplaues may be de- 

 fined as follows (adapted in part from Fischer) : 



Mycelium as in Achlya. Sporangia extremely scarce, often entirely 

 absent for long periods in culture, cylindrical, renewed as in Saprolegnia 

 and perhaps also as in Achlya; spores at times escaping, at times retained 

 in the sporangium and sprouting there, their behavior not well known. 

 Oogonia abundant, in chains or single and terminal, barrel-shaped, 

 spherical or pyriform, their walls very thick (more so than in other water 

 molds) and heavily pitted. Antheridial branches arising from imme- 

 diately below the oogonia, or when the oogonia are in chains arising from 

 the top of one oogonium and attached to the next above, simple or 

 branched, the antheridia with their sides attached to the oogonia. Eggs 

 centric, at times elliptic from pressure. 



1. Aplanes androgynus (Archer) Humphrey. Trans. Am. Phil. Soc. 

 17: 134. 1892 [1893]. 



Saprolegnia androgyna Archer. Quart. Jour. i\lic. Sci. 7 n. s. : 123, 



pi. 6, fig. I. 1867. 

 Achlya Braunii Reinsch. Jahrb. f. wiss. Bot. 11: 284, pi. 14, figs. 



1-6. 1878. 

 Aplanes Braunii deBary. Bot. Zeit. 46: 650, pi. 9, fig. 2. 1888. 



This has been reported five times: by Archer from England, by 

 Petersen ('10, p. 526) from Denmark, and by Reinsch, deBary and 

 Minden from Germany. It is easily recognized by the \ery scarce 

 sporangia, by the peculiar oogonia which are often in chains, their walls 

 thick and very strongly pitted, their shape subspherical or more often 

 spindle-shaped or pyriform or barrel-shaped, and by the antheridial 

 branches which are slender, often branched, springing from immediately 

 beneath each oogonium and pressed against it, with small antheridia 

 on their tips. Eggs numerous, centric, 22-34;j. thick (Minden). Oogonia 

 about 65-90 X i20-i6o!x. 



Archer describes his plant thus: 



"Plant monoecious; oogonia large, barrel-shaped or elliptic, mostly 

 in an uninterrupted terminal series, though occasionally interstitial; 

 the terminal oogonium the oldest in a series, the oogonia thus showing 

 gradually difterent degrees of de\elopment down to the basal one which 

 is the youngest; the lateral male branches, with the exception of those 

 fertilizing the lowest oogonium of a series, are not derived either from 



