Il6 THE SAPROLEGNIACEAE 



of the oogonial stalk towards the end (fig. 6), and by the hyphae not 

 rarely coiling themselves into a flat spiral like a watch spring. 



The antheridia while usually in the great majority diclinous are not 

 consistently so and are very variable in this respect. On mushroom 

 grubs or bits of boiled corn grain very few androgynous antheridia may 

 appear or they may be numerous, these changes appearing in consecu- 

 tive cultures of the same pure strain. 



9. Achlya flagellata n. sp. 



Plate 37 



Growth stout and moderately dense, reaching a length of about 

 I cm. on a mushroom grub or ant larva. Hyphae branching, tapering 

 outward, up to i50iA thick near the base, more or less crowded and un- 

 even, the tips hyaline and often dying and renewed from one side below 

 as in all members of this group. Sporangia plentiful, subcylindrical, 

 very variable in size, often bent and at times with more than one open- 

 ing, scattered or clustered. Spores often falling to the bottom in an 

 open cluster on emerging, about ii-ii.5tji. thick. Gemmae abundant, 

 usually in rows from the segmentation of the distal parts of hyphae, 

 short or long, usually more or less cylindrical, but often pear-shaped or 

 ten-pin-shaped or at times very irregular; usually becoming sporangia 

 on change of medium and discharging through an elongated papilla at 

 either end. Oogonia abundant, typically spherical, but not rarely ir- 

 regular by abnormal growth on one side, and one or two papillate projec- 

 tions may be seen rarely; usually about 48-75-^ thick, rarely up to ioo;i, 

 racemosely borne on short, slender stalks about as long usually as the 

 diameter of the oogonia or a little shorter, rarely on longer stalks and 

 quite rarely intercalary; wall hyaline, not thick (about 1.5^/.); pits very 

 variable, perhaps more often absent, but again numerous and rather 

 easily seen, about 5.511. wide. Eggs spherical, eccentric with a large oil 

 drop, i-io (rarely 20) in an oogonium, mostly 2-6, diameter 26-3510., 

 most about 28sx, rarely small ones down to iSyi may be mixed with the 

 others. Antheridial branches abundant, usually much branched and 

 irregular, often so much so as to make an intricate network like a group 

 of rhizoids, originating laterally and apically from hyphae which may or 

 may not bear oogonia and applying themselves to oogonia on the same 

 or on other threads or to both; more often diclinous than androgynous, 

 perhaps about three times as often usually, but varying in this respect; 

 the antheridial branches never arising from the stalks of the oogonia. 

 Antheridia on nearly all oogonia, one or several, elongated with the side 

 on the oogonium, frequently touching the oogonium with foot-like pro- 

 jections; antheridial tubes easily observed. 



Very common in Chapel Hill in springs, brooks, ditches and creeks, 

 as in spring near Clark's schoolhouse (No. i of July 25, 1918), in Arbore- 

 tum spring, in Battle's branch, etc. Also found in some material sent from 

 Chimney Rock, N. C, June 10, 1920 (Miss Hoffmann, coll.), differing from 



