ACHLVA 143 



is not comparable, as Davis claims, to the coenocentrum of the Pero- 

 nosporeae. 



Achlya prolifera (Nees) dcBary. Hot. Zeit. 10: 473, pi. 7. figs- 1-28. 



1852. 



As this plant has not been found in America, at least in its typical 

 form,* we include it here, and make the following translation of deBary's 

 later description {'SS, p. 633): 



"Main threads stout, usually ending with primary sporangia, under 

 which the secondary are formed sympodially. Oogonia racemosely 

 arranged on short side branches of the main hyphae, as a rule terminal, 

 round, the wall with numerous, very sharply defined and obvious pits. 

 Eggs variable in number, mostly numerous, eccentric. Anthcridial 

 branches diclinous, much twisted and branched, winding like a parasite 

 about the oogonia and the threads which bear them; the oogonial walls 

 thickly enwrapped and often completely covered by these liranches 

 which bear numerous, at times intercalary, antheridia, which lay their 

 sides against the oogonium and send out fertilizing tubes. 



"The most abundant of all Achlya species occurring everywhere." 



For a more extensi\e account with numerous good figures see deBary's 

 first treatment ('81), pi. 2, figs. 1-2; pi. 4, figs. 1-4. In this he shows 

 oogonia with eggs varying from i to 16 or 20, but mostly 2-3. Also see 

 Unger ('43), pi. 4; Maurizio ('95a), figs. 4-5; Minden('i2), figs. 2b, 2d 

 on p. 520. 



For remarks on this species see under A. proliferoides and A. im- 

 perfecta. According to Maurizio ('95a), A. prolifera is often parasitic 

 on fish. According to Cienkowski ('55), the eggs may sprout directly 

 into zoospores. 



Achlya aplanes Maurizio. Flora 79: 135, pi. 4-5, figs. 28-31. 1894. 



The following is adapted from the original: 



The sporangia frequently retain the spores and in such cases they 

 sprout to threads. Xo net sporangia seen. If the spores emerge they 

 sprout at the mouth; and in no case do they have a swimming stage. 

 Fig. 29, plate 5, shows the spores sprouting at the tip of the sporangia 

 after discharge. .Segments of hyphae often cut off below sporangia 

 to form others. Oogonia racemose (as in A. prolifera) on short stalks 

 or also at times terminal, intercalary or lateral just under a sporangium; 

 spherical (42-58. 5.x) or the intercalary and end ones mostly egg- to flask- 

 shaped (56 X 6o;x) ; wall smooth, fairly thick, clear yellowish, usually 

 with 2 or 3 pits, or without any pits. A young oogonium often pro- 



* Under the name ^1. prolifera, Pieters publishes observations on an Achlya from Ann 

 Arbor in the Am. Jour, of Bot. (2:529. 1915; also recorded in Ann. Rep. Mich. Acad. 

 Sci. 8: 27. 1905), but as his unpublished drawings, kindly submitted to us, show a plant 

 that could better be referred to A. imperfecla, we have noted it under that species. 



