THE WILT DISEASE OF PIGEON-PEA. 45 
colourless but in the mass range from flesh colour to deep salmon 
pink on most media. They give a peculiar moist, almost oily, ap- 
pearance to the surface of the growth from their great numbers. 
They are formed either on single conidiophores arising directly 
from the creeping mycelium (plate IV, fig. 2), or on special whorled 
branches in dense clusters (fig. 1). If there is any morphological 
character which distinguishes this species from its allies, it is 
this formation of crowded whorled conidiophores. I have not ob- 
served them in other species seen. They are not, however, always 
formed and the other type, which is always present, is not 
distinguishable from that of several allied species. 
Even at an early stage of the cultures septate spores are form- 
ed. The typical forms found at this period are straight or slightly 
curved, continuous and measure 5 to 15 by 2to4u. The other forms 
which occur mingled with these are falcate or strongly lunulate, 
single-celled spores, larger than the last (up to 214 im length), and 
one, two or sometimes three-celled spores, which may be straight 
or curved and with pointed or rounded ends. Examples of all the 
types seen in a single culture on the third day are shown on plate 
IV, fig. 4. 
In a few cultures on potato and plantain, small round sclerotia, 
bearing microconidia, appeared. These seem to correspond to the 
Tubercularia stage of Nectria cinnabarina. 
Many of the cultures, especially some of those on liquid media, 
formed no other kind of spore but the above. In others Fusarium 
spores develop. They appear later than the other forms and are 
figured in plate IV, fig. 7. Quite similar spores may be got from 
any culture by inoculating a drop of agar on a slide, and it appears 
probable that they occur regularly in all good solid-medium cultures 
that are well aerated, but less frequently in liquid media or in badly 
aerated cultures. 
The Fusarium type of spore may be formed either singly on 
short lateral conidiophores, or in clusters. A true tubercularia- 
ceous stroma bearing macroconidia has not developed in any of the 
