134 THE SAPROLEGNIACEAE 



rarely two in an oogonium, eccentric, their diameter i5-23;x, averaging 

 about 20;x. Antiieridia absent from a good many oogonia, when present 

 club-shaped; borne on the tips of branches from the same glomerulus 

 and one or several on an oogonium (fig. 5). 



This species has been observed several times from two stations 

 at Chapel Hill, North Carolina. The drawings are made from material 

 taken from a cool spring in dense woods (Lone Pine spring) on April 30, 

 1912, and from the springy marsh at the foot of Lone Pine hill on Feb- 

 ruary 29, 1912. Pure cultures have been continued for six months or more. 



This species does not closely approach any other, but it seems to 

 be nearest the members of the Racemosa group. The shape of the an- 

 theridia is like those of A. racemosa and its relatives, and there is con- 

 siderable resemblance to the spiny oogonia of A. colorata and A. radiosa. 

 There is also some hint of the habit of ^. glomemta in the occasional branched 

 oogonial threads of A. radiosa. In all the members of the Racemosa group 

 the antheridial branches, when present, originate just below the oogonium. 

 In A . glomerata they do not thus originate. This distinction with the usually 

 bent and twisted branching habit of the oogonial hyphae separates 

 the species sharply from any of the Racemosa group. As already men- 

 tioned, the oogonia are sometimes borne singly on the ends of simple 

 branches, especially near the tips of the main hyphae, but in such cases 

 these branches are much more delicate and longer in proportion to the 

 oogonia than is generally the case in any member of the Racemosa group. 

 Achlya spinosa has but one or two eggs (rarely three) in an oogonium 

 and may be the closest relative of A. glomerata. It differs easily in the 

 barrel-shaped oogonia with an apical papilla, in the antheridia arising 

 just beneath the oogonia, and in the absence of clustered groups of 

 oogonia. 



The fruiting branches are so abundant and many of them are so 

 elongated and extensively branched that the cultures take on a whitish, 

 cottony appearance except near the periphery, which is usually without 

 branches. In extreme cases this effect is so pronounced that the culture 

 may be compared in appearance to a rug with a fringe. This reminds 

 us of the "woolly snow-white turf" produced by deBary's Achlya spinosa 

 ('88, p. 647), Avhich species, while not in the close family circle of the 

 Racemosa group, shows its relation to them by its spiny oogonia with 

 generally one egg, and by the origin and shape of the antheridia. 



So far as the sexual organs are concerned, there is a remarkably 

 close resemblance between Achlya glomerata and Saprolegnia asterophora 

 deBary. As in most species of Achlya, the spores sometimes remain 

 in the sporangium and sprout there (Coker, '10, p. 381). 

 Pure cultures from No. 10 of April 30, 1912: 



