322 
Journal of Agricultural Research 
Vol. VIII, No. 9 
CONIDIAE STAG $ 
Observations on the development of the conidial stage agree essen¬ 
tially with those of Thaxter. 1 The erect conidiophores, whose com¬ 
parative size is shown in Plate 87, A , are whitish at first, but at ma¬ 
turity change to a distinct metallic luster. They are broadest at the 
upper extremity, which becomes dilated into a capitate vesicle. From 
this capitulum, a few to a dozen or more ramuli arise, which in turn 
become vesicular (PL 85, A ). The ramuli commonly remain simple, 
but occasionally branched ones are present. By a process of budding, 
an early stage of which is represented in Plate 85, B , the capitella become 
covered with a densely compacted layer of conidia (PL 85, D). The 
conidia vary in outline from oval to elliptical and are conspicuously 
marked by longitudinal striations (Pl. 85, C), some of which anastomose. 
They vary in size from 15 to 25 by 7.5 to 11 u and in color from light 
brown to reddish brown. The base of each conidium is provided with a 
hyalin appendage, the adherent portion of the sterigma. When the 
ramuli are broken off, scars as shown in Plate 85, E> are evident on the 
primary vesicle. 
Variations from this normal course of development have been noted. 
Conidia may arise directly from the surface of the primary head, a condi¬ 
tion noted both by Thaxter 1 and myself and which is characteristic of 
the genus Rhopalomyces. Occasionally the conidiophore branches and 
gives rise to two primary heads on each of which a layer of conidia is 
formed. These are not necessarily depauperate forms, since they appear 
in cultures with normal well-developed conidial fructifications. 
GERMINATION OF CONIDIA 
Germination readily follows when the conidia are sown either on nutri¬ 
ent agar, such as bean, potato, glycerin, or cellulose agar, or in drops of 
water. Cunningham 2 states that germination of conidia of C. infundi - 
bulifera does not occur in water. Germination of C. cucurbitarum does not 
proceed, however, with equal rapidity in water and in nutrient agar, as 
shown by Plate 85, G, H , the former of which represents growth on nutri¬ 
ent agar 3 % hours after the commencement of cultivation, and the latter 
growth in water, after an equal period. Conidia were obtained from 
the same source in both cases and were germinated under the same con¬ 
ditions of light and temperature. 
The first evidence of germination is the considerable increase in size 
which takes place before the emergence of the germ tube. Typically a 
single lateral germ tube is formed, occasionally two, which in some cases 
arise from the extremity. As a rule, the germ tubes will have emerged 
within two hours after sowing. The rate of subsequent development is 
indicated in the stages represented in Plate 85, /. Plate 85, /, a, shows 
1 Thaxter, Roland. Op. cit. 
1 Cunningham, D. D. Op. cit. 
