] 22 THE SAPROLEGNIACEAE 



spores sprout in position, most of the sprouts remaining inside the spor- 

 angium, others emerging through the opening or directly through the wall. 

 No well-developed dictiosporangia have been seen in our cultures, but 

 when the spores are all retained in the sporangium a few of the peripheral 

 ones may emerge exactly as in Dictyuchus, the majority emerging from 

 their cysts to swim inside as described above. Sporangia of the Aplanes 

 type with all the spores retained and sprouting with germ tubes through 

 the sporangium wall are not rare (fig.io), but the tubes are not vigorous 

 in such cases and soon die. 



12. Achlya caroliniana Coker. Bot. Gaz. 50: 381. 1910. 



Plate 41 



Hyphae rather stout, about 48;x thick at the base and 20;j. near the 

 tip, in strong cultures reaching a length of 1.5 cm. Sporangia irregularly 

 cvlindrical, about 20-301J. in diameter, often discharging by several open- 

 ings, sometimes remaining closed and emptying as in Dictyuchus, cili- 

 ated on emerging but behaving as in other Achlyas. Spores ii-i2[i. in 

 diameter, most about i i.2yi. Oogonia abundant, very small, 24-5510. thick, 

 most about 30-37[j., spherical when terminal, wall smooth, or not rarely 

 with one or two papillae or angles, thin, not pitted, light yellow in age, 

 terminating short or moderately long, slender branches, which are racemose- 

 ly borne on the strong main hyphae, or rather rarely intercalary and elon- 

 gated, at times filiform with several elongated eggs in a row. Oogonial 

 branches generally simple, but often giving off near the base, or sometimes 

 near the oogonia, one or two branches which also terminate in oogonia, 

 and, as a rule, are curved downward. Eggs generally 1-2, not rarely 

 4, eccentric, with a large oil globule, 18.5-231X in diameter, averaging 

 about 22(jL, often elongated by pressure. Antheridia absent. A papilla, 

 thick-walled and soon empty, often grows into the oogonium through the 

 basal partition exactly as in other members of the Prolijera group and in 

 A. hypogyna. 



Distinguished by the absence of antheridia and by the small, un- 

 pittcd oogonia with a few small eggs. 



Rare in pools and small streams, such as Arboretum branch. Battle's 

 branch, small pools in pasture below Purefoy's Mill, etc. Appeared five 

 times in Chapel Hill collections before December 15, 1913 (see table on p. 14). 



This species is particularly interesting in that it is the only species 

 in the Prolijera group without antheridia. It is almost exactly like A. im- 

 perfecta in other ways (except for absence of pits). 



The cultures in the following experiments were made from a pure 

 culture on corn meal agar of No. 10 of March 20, 1913, using egg yolk 

 as the food material: 



In .1% KNOj. Limited growth of rather coarse, strong hyphae, as in the following three 

 experiments. Sporangia present. Oogonia on smaller hyphae, but eggs not maturing. 



