100 THE SAPROLEGNIACEAE 



Antheridia absent; eggs usually I or 2; oogonia smooth or with a few papillate 



outgrowths A. caroliniana (12) 



Apicidata Group: Eggs in all American species not filling the oogonium and often far 

 from filling it, subcentric, with one or more rows of inconspicuous droplets all 

 or most of the way around the globule of jjrotopiasm which is nearer one side 

 than the other;* oogonial wall unpitted except in A. conspicna 

 Eggs few (usually 1-5), most about 36^ thick; oogonia often with an apiculus; 



antheridia in greater part androgynous A. apicidata (13) 



Eggs few (usually i or 2), most about 45m thick; otherwise as in .1. apicidata 



A. apicidata van prolifica (14) 

 Eggs usually 4-6, about 45^ thick; oogonium without an apiculus 



A. megasperma (15) 

 Eggs more numerous and smaller 



Oogonia smooth, antheridia androgynous A. polyaiidra (l6) 



Oogonia smooth, antheridia both androg\-nous and diclinous 



A. conspicna (17) 

 Oogonia smooth, antheridia diclinous 



Oogonia subspherical to short pyriform, their stalks long 



A. oblongata (18) 



Oogonia spherical, their stalks short A. oblongata var. globosa (19) 



Oogonia papillate; antheridia diclinous and androgynous 



Oogonia with l-io papillate projections; eggs usually 4-8 



A. oligacantlia (p. 144) 

 Oogonia with more numerous papillate projections; eggs usually about 10 



A. rccurva (p. 144) 



Sub-genus Glomeroachlya: Oogonia often borne in branched glomeruli, very small, 



their unpitted walls thickly covered with blunt warts; eggs single, eccentric; antheridial 



branches androgynous and arising near the oogonium, but at times a little branched; 



antheridia as in Centroachlya. There is but one species in the sub-genus. 



A. glomerata (20) 



Sub-genus Thraustoachlya: Eggs eccentric with a single large oil drop outside of the 



protoplasm at full maturity. Antheridia all diclinous and present on all oogonia. 



Oogonial wall >ellowish. Sporangia often releasing the spores by disintegration as in 



Tliraiistotlieca. There is but one species in the sub-genus A. diibia (21) 



Position doubtful; oogonia absent Acldya sp. (22) 



Artificial key to the Species of AcHLYAf 



I. Oogonia absent Acldya sp. (22) 



I. Oogonia without spines or papillate outgrowths or only a few of them with such pro- 

 jections - 



1. Oogonia mostly with spines or papillate outgrowths 11 



2. Antheridial branches almost always androgynous 3 



2. Antheridial branches diclinous or both diclinous and androgynous 6 



* The exact structure of the eggs in A. oligacantlia and .1. polyandra is not known. The 

 eggs of the first are described as "centric" by deBaryand those of /I. grac//i>M, which maybe 

 the same as the second, he also describes as centric, and we have no data on the egg structure 

 of A. recnrva. Other characters, however, point to their inclusion here. 



t American species are followed by a number; European by a page reference. 



