Vol. II, No. 4 
272 Journal of Agricultural Research 
change in its known characters. Sometimes the production of conidia 
preceding that of the perfect form is more abundant and lasts longer in 
one culture set than in another of the same strain, but the constancy has 
been found a function of the constancy of method and medium. The 
conidia showed a remarkable constancy in shape and size (PI. XIII, 
fig. G) and had 3 to 5 septa. There was, of course, a fluctuation in the 
percentage of 3-, 4-, and 5-septate cojiidia, depending on the medium 
itself and on the age of the culture. Once the triseptate conidia prevailed, 
and sometimes the quinqueseptate conidia prevailed, but this fluctuation 
is constant even if 5-septate conidia are transferred separately. In other 
words, strains can not be grown with only 5-septate conidia by repeated 
selection of 5-septate conidia from a fungus with a normal fluctuation of 
3- to 5-septate conidia. 
In overwatering Hypomyces ipomoeae , its septate mature conidia 
swell and germinate if sufficient food allows further vegetative growth. 
If the medium is very dilute so that macroconidia can not be formed, 
microconidia will take their place (PI. XIII, fig. F). While in almost 
pure water chlamydospores similar to those known in the section Martiella 
of Fusarium appear on hyphae (PI. XIII, fig. D , 1-3) or within conidia 
(conidio-chlamydospore, PI. XIII, fig. D, 4). A transfer to a better 
medium, such as potato tuber or stems of legumes, will be helpful to pro¬ 
duce perithecia. The young perithecium illustrated in Plate XIII, figure 
E, originated from a side branch of a proliferous hypha. The same spiral 
rolling up can be seen in Neocosmospora. The fungus requires 10 to 14 
days for the mature red perithecia (PI. XIII, fig. C) to disseminate their 
ascospores. If in the meantime cross sections are made from perithecia 
in various stages of their development, the asci and their remarkable 
variations from cylindrical to clavate forms can be followed (PI. XIII, 
fig. B). Paraphyses appear occasionally, but in many preparations they 
are invisible, owing to their fragility and scarcity. Perithecia may be 
illustrated with prevalently cylindrical asci, with the clavate form, and 
with mixtures of both types, depending on the water content of the 
culture and other conditions. The shape of the asci is so modified by the 
elasticity of their membrane that this character does not seem to be of 
taxonomic importance. Water influences the outline of ascospores. 
Barrel-like, swollen cells (PI. XIII, fig. A, 3) indicate either overmaturity 
in the presence of too much water or the stage before germination. If 
the medium is exhausted with water still present, a separation of the two 
cells can often be seen (PI. XIII, fig. A, 4). This resembles Hypocrea. 
A slow desiccation of the culture performed after the maturity of the 
perithecia prevents a swelling of the ascospore and normal mature spores 
of ellipsoidal shape will prevail (Pl. XIII, fig. A, 1). Complete dryness 
decreases the turgescence, so that mature cells become conical with 
rounded top. Immature spores, however, may look more pointed then 
