ISOACllI.VA 81 



have appeared in our cultures, and we arc inclined to think that such 

 hyphae, with such thick walls, are only occasional in the European plants. 

 They are not shown or mentioned by Reinsch. 



The sporangia and spores of this species are scarcely better known 

 or more consistently described than in .1. androgyniis. Humphrey saw 

 no sporangia, but placed the species in Saprokgnia because Trelease saw 

 one sporangium which he said was like those of Saproleguia and which 

 he drew empty with an open tip (Humphrey, '92, pi. 17, fig. 56). Reinsch 

 (pi. 14) gives three figures showing external proliferation through empty 

 sporangia, but gi^-es no detail as to the jjchavior of the spores. Petersen 

 ('10, p. 520) refers his plant to Saprokgnia with much doubt and solely 

 on the proliferation of the sporangia. He does not mention the spores or 

 their behavior, a fact which indicates that the sporangia were rare. 

 Minden (I.e.) does not mention the sporangia and spores in the body of 

 his description of his var. tttrfosa, but says the plant cannot be Achlya 

 racenwsa because of the method of spore escape and the long, internally 

 proliferating sporangia. KaufTman ('05, p. 27) finds the species in 

 Michigan and transfers it to Achlya as "the sporangia emptied in the 

 manner of Achlya; in every other respect it agreed with Saprokgnia 

 Trekaseana Humphrey, and is no doubt the same plant." 



As to ourselves, we can add little to clear up the uncertainty. The 

 very few sporangia we ha\-e seen looked like those of Saprokgnia and had 

 emptied at the tip and proliferated internally (figs. 2 and 3 ; emptied gemmae 

 are also shown). We ha\-e not seen the spores emerge. Our experience 

 emphasizes the very great rarity of the sporangia. The ones shown were 

 from our first collection (1918) which was unfortunately lost during 

 the summer vacation. The other collection (1922) yielded not a single 

 sporangium, although cultivated for about three months on many sorts 

 of media and in different temperatures with this object in view. Media 

 used were flies, termites, mushroom grubs, corn grain, lieans, etc. 



ISO.ACHLYA Kauffman, 1921, p. 231. 



Hyphae rather stout or slender. Zoosporangia formed from their 

 tips, oval, pyriform, ventricose-clavate, elongated pyriform to clavate 

 or cylindrical-clavate; the later ones (secondary) arising either by 

 cymose or pseudo-cymose arrangement, as in Achlya, or by internal pro- 

 liferation as in Saprokgnia, both modes occurring earlier or later in the 

 development of one and the same species, or frequently on the same main 

 hypha. Zoospores diplanetic, as in Saprokgnia, escaping and swarm- 

 ing separately, and after encystment swarming the second time before 

 the formation of a germ-tube. Oogonia terminal or torulose, occa- 

 sionally intercalary. Oospores with centric or eccentric contents, the spores 

 filling the oogonium incompletely. Anthcridia present or few to none. 



