124 THE SAPROLEGNIACEAE 



are usually bent and sometimes make a complete turn, rarely interca- 

 lary, ovate, short pyriform or spherical, at low temperatures very rarely 

 formed within empty sporangia (as in Saprolegnia ferax), typically with 

 (but often without) a more or less prominent apiculus; 60-1 iQfi. thick, 

 most about 8o;j.; walls thin, smooth, unpitted. Eggs few, large, very dark, 

 subcentric, 1-5, usually 2 or 3 (rarely 10), 25-40^1 thick, sometimes 

 larger, average about t,6'x. Antheridial branches usually androgynous, 

 but often diclinous, arising from the main hyphae or from the oogonial 

 branches, soon becoming inconspicuous. Antheridia small, tuberous or 

 cylindrical, usually one or more to each oogonium. 



The species is plentiful, especially in winter and spring, in branches, 

 outlets of springs, edges of meadows, etc., as in Arboretum spring and 

 branch, Battle's spring and branch. Glen Burnie meadow. We find it 

 also at Tarboro, N. C. (A'larch 7, 1921). Collected 94 times between 

 February 15, 1912, and December 12, 1913 (see table on p. 14), and often 

 since. Reported heretofore in America only by Humphrey from Massa- 

 chusetts and by Atkinson from Alabama. For other illustrations see Ward 

 ('83), pi. 22, figs. 15 and 16; Humphrey ('92), pi. 15, figs. 26 and 27; pi. 

 19, figs 82-86. 



A single antheridial branch may, on reaching the oogonium, branch 

 so extensively as to net the whole surface, but frequently no proper 

 antheridium is cut oft", and the embracing processes are not very densely 

 filled with protoplasm. As in A. oblongata the eggs go to pieces so 

 soon that it is exceptional that the final structure of maturity is reached. 

 The homogeneous and almost black appearance of youth (transmitted 

 light) gradually becomes more granular and lighter. Just before disor- 

 ganizing the structure is that of a large central globule nearer one side than 

 the other and apparently protoplasmic, completely surrounded by darker, 

 rather dimly defined fatty globules. This agrees very well with deBary's 

 description and figure except that he considered the central mass as a 

 fat globule. In both this species and its variety prolifica the oogonial 

 apiculus when present is not the result of an outgrowth from a spherical 

 oogonial initial, but represents the unswollen tip of the original branch 

 which produced the oogonium by an inflation below. If the tip is rather 

 long the oogonia tend to be somewhat o^'al. 



The spores develop exactly as described for Saprolegnia anisospora. 

 The spore units appear, then disappear again about five or ten minutes 

 before emergence, then gradually reappear, but with less clear outline, 

 then the entire spore mass is slightly drawn away from the walls (most 

 noticeable in A. apiculata in basal part, but to be made out all over), 

 and the discharge occurs in a few minutes. The whole spore mass 

 holds closely together and makes a central column, emerging as one 

 body, with nf) indi^'idual motion visible, thus showing without any doubt 



