194 
A. E. Lechmere. 
bb. Antherocyst formed from a separate filament. 
a. Antheridial filament arises as a separate 
branch from the main hypha (diklinous).] 
ax. Oospore concentric, zoospores all of one 
kind. 5. dioicci (2). 
/3/S. Oospores excentric, zoospores of two 
kinds. S. cinisospora (J). 
/3. Antheridial filament arises from same main 
hypha which bears the oocysts (andro¬ 
gynous). 
ax. Antherocysts always present. 
5. monoica (4). 
/3/3. Antherocysts only present in 50% cases. 
5. mixta (5). 
B. Antherocyst nearly always absent. 
aa. Oocysts borne singly. Main hyphse robust and 
of even thickness. Antherocyst never present. 
>S. Thureti (6). 
bb. Oocysts often in rows, main hyphas lax, and 
later become divided into segments forming 
gemmae, oocysts or secondary sporocysts. 
Antherocysts sometimes present. 
5. tonilosa (7). 
(2). Oocysts contain many oospores and become 
detached from the hpyha before the oospores 
are mature, or only remain very slightly 
attached. New sporocysts arise by upgrowth 
within old wall or by cymose branching of the 
hvphas. Monilifera Group. 5. Monilifera (8.) 
II. Oocyst spiny, star-shaped, only contains one oospore. New 
sporocyst arises by upgrowth of hypha within 
the old wall. 
~Asterophora Group. 5. Asterophora ( 9 ). 
