1052 
Journal of Agricultural Research 
Vol. XXX, No. 11 
lar appearance, and individual conidia 
may be observed with a low-power 
hand-lens along the edges of the 
growth when it has reached the glass 
sides. Frequently each lateral branch 
of a hypha becomes a conidiophore 
off by a septum and drops off. Per¬ 
sistent conidia and germination in situ 
are exceptional. Zoospore formation 
has not been observed, even when the 
same environmental conditions are 
applied which induced their formation 
15 16 V 18 19 2 0 21 22 23 24 25 26 2 7 28 29 30 31 32 33 3 4 35 36 57 38 39 40 
DIAMETER IN MICRONS 
Fig. 1.—Measurements of oogonia of P. debaryanum (300) and of P. splendens (400) plotted as frequency 
curve 
Fig. 2.—Measurements of oospores of P. debaryanum (300) and of P. splendens (400) plotted as frequency 
curve 
(pi. 4, A). The most prolific appear- in Pythium complectens. When placed 
ance of these bodies was observed in in distilled or tap water, in potato 
colonies held at 30° C., which is also juice, prune juice, and oatmeal decoc- 
the optimum temperature for mass tion, from two to six tubes are put 
growth. forth from each conidia, the number 
Germination in A may take place being larger in the richer substrata, 
immediately after the conidium is cut The latter also induce more rapid and 
