WITH XOTES ON OTHER SPECIES. 125 



ACHLYA PAPILLOSA sp. nOV. 



111. : PI. XX, Figs. 99-102. 



Hyphse rather slender, long. Zoosporangia sparingly developed, cylindrical, 

 little larger than the hyphse. Oogonia terminal on main threads or on short lateral 

 branches, or sometimes intercalary, oval or ovate, rarely globular, thickly studded 

 with short, blunt, wart-like outgrowths of their unpitted walls, often with a marked 

 apiculus, Antheridial branches usually developed with each oogonium, fine and branch- 

 ing, arising near it from the main thread, or rarely from the oogonial branch. Anther- 

 idia imperfectly formed. Oospores as many as twelve in an oogonium, oftenest four 

 to six, centric, their average diameter about 25;y.. 



Massachusetts — Amherst. 



This plant, which seems to be sufficiently distinct from previously described spe- 

 cies, has been obtained in several cultures, but from only a single source ; namely, the 

 very prolific mossy pool in Amherst, already mentioned. It may be recognized by its 

 long hyphse, finer than those of most Achlyce, and its oogonia with warty, rather than 

 spiny, walls, and several oospores in each. I have never seen well- differentiated 

 antheridia or fertilization-tubes, although the ends of the antheridial branches are 

 applied to the oogonia. 



While bearing no near resemblance to any species heretofore figured, this plant 

 may be somewhat closely related to the next, if the latter is well founded. 



AcJilya recurva Cornu ('72). 



So far as the incomplete account published by its author enables one to judge, this 

 is a distinct species from the last, and is separated by its longer and recurved oogonial 

 branches, on which the oogonia are usually borne laterally, and by its better 

 developed antheridia, often digitately branched. Aside from the original observations 

 of its author ('72), this species has been recognized only by Hartog ('88). 



Achlya spinosa DeBary ('81). 



111.: DeBary, '81, PL IV, Figs. 13-18. 



Its author's latest description of this species ('88) does not fully agree with his 

 earlier figures ('81), especially in that he states that the oogonia are never intercalary, 



