SAPROLEGNIALES 841 



TAXA NOT IN COKER (1923) OR COKER AND MATTHEWS (1937) 



Protoachlya hypogyna Shanor and Conover 

 Amer. Midi. Nat., 28: 747. 1942 



Protoachlya polyspora (Lindstedt) Apinis 

 Acta Horti Bot. Univ. Latv., 4: 224, pi. 3, figs. 1-15. 1930 



ACHLYA C. G. Nees 



Nova Acta Acad. Leop. -Carol., 11 : 514. 1823 

 (Fig. 65 F-G, p. 836) 

 Hydronema Carus, Nova Acta Acad. Leop. -Carol., 11 : 491. 1823 

 "Thalli monoecious or dioecious. Hyphae stout or slender, more or 

 less branched, straight or flexuous, gradually tapering from base to 

 apex; variable in length. Gemmae, when present, formed by segmen- 

 tation of the hyphae; variable in size and shape; functioning as zoo- 

 sporangia or germinating by one or more slender hyphae which usually 

 terminate in a small zoosporangium. Zoosporangia filiform, fusiform, 

 naviculate, or clavate; renewed sympodially or by basipetalous devel- 

 opment and cymose branching. Zoospores usually dimorphic; primary 

 ones on discharge encysting at once to form a more or less spherical, 

 hollow mass at the zoosporangial orifice and occasionally provided 

 with two quickly evanescent, apically attached flagella during emer- 

 gence ; secondary zoospores reniform, laterally biflagellate, germinating 

 after encystment by a slender hypha; in a few species, aplanoid, dic- 

 tyoid, or thraustothecoid discharge also present. Oogonia borne var- 

 iously, being lateral on stalks of variable length, terminal, intercalary, 

 or sessile; in some species, the immature ones proliferating; variously 

 shaped, predominantly spherical or pyriform. Oogonial walls with or 

 without ornamentations; pitted or unpitted. Antheridial branches di- 

 clinous, monoclinous, androgynous, or exigynous, in one species hy- 

 pogynous; in a few species lacking. Antheridial cells predominantly 

 tubular and clavate; laterally or apically appressed to the oogonial 

 wall or attached by finger-like projections; fertilization tubes usually 

 present. Oospheres generally maturing. Oospores one to many; centric, 

 subcentric, or eccentric; germination, when present, usually accom- 



