62 BULLETIN 934, U. S. DEPARTMENT OF AGRICULTURE. 
siana in pots of autoclaved soil which had received tap water at 
Washington, D. C. It agreed both in the appearance and measure- 
ments of its spiny oogones and smooth oospores with Pythium arto- 
trogus {P. hydnosporus) as described and figured by Butler (23). 
In addition to the spores which Butler describes, there appeared in 
apparently pure prune-agar cultures of different strains bodies with 
smooth walls, of somewhat irregular ovoid outline, and mostly larger 
than either oospores or oogones. They are very much less abundant 
than the sexual spore forms. Their greatest diameter varied from 
11 \l to over 40 \l. The germination of these bodies was not observed. 
Efforts to induce the fungus to produce swarm spores by growing 
them in liquid nutrient media and transferring them to pure water 
were unsuccessful. This failure to produce zoospores is further in- 
dication of the identity of the fungus with that described by Butler, 
who says that asexual reproduction is unknown. 
The strain from Michigan was a rather weak growing organism, 
difficult to maintain in tube cultures without rather frequent trans- 
fers. Its parasitic activity in the experiments reported in Table VIII 
is nil or negligible. Because of the poor seed and small number of 
seedlings involved in experiment 72B, the percentage of damping- 
off there given means only a single seedling dead. The Washington 
strains, on the other hand, though evidently not strong parasites, did 
apparently cause the death of a number of seedlings. The best evi- 
dence of this is in experiment 68, in which there was damping-off 
in each of the five 5-pot units containing the Washington strains and 
none in any of the 18 control pots. The available strains were less 
active not only than PythiuTn debaryanum^ but less than the Rheo- 
sporangium and Phytophthora strains used. The fungus is be- 
lieved to be a potential parasite on pine seedlings, but not one of am r 
general importance. What is probably the same fungus had ap- 
peared in the writer's cultures from western nurseries in conjunc- 
tion with P. debaryanum, but not commonly, and it had not been 
isolated. While its growth rate is only about half that of Pu debary- 
anum on prune agar, it is nevertheless so much faster than that of 
many fungi that it should have been more often obtained in culture 
were it at all common in damped-off seedlings. 
Another fungus, presumably an oomycete but producing only 
chlamydospores in the writer's cultures, was obtained from damped- 
off olive seedlings furnished by Prof. W. T. Home and from soil 
direct, both at 'Berkeley, Calif. The fungus is apparently the same 
as one which has been occasionally seen in cultures from pine seed- 
lings in the Middle West, but had not before been isolated. The 
hyphse are ordinarily nonseptate, and the growth on corn-meal agar 
is superficially much like that of Pythium debaryanum, but with 
greater tendency toward local zonation and aerial growth and less 
