18 BOTANICAL GAZETTE [yoLy 
small, pycnidia. Transfers made again from these two strains 
resulted in a complete reversal of character, the fertile becoming 
sterile and the sterile becoming fertile. No explanation of this sug- 
gests itself. 
When this fungus was plated from a suspension of spores, two 
types of colony developed, corresponding to the two strains mentioned 
Fic. 13.—Ascochyta Chrysanthemi Stevens; portion of colony showing few 
pycnidia; cf. fig. 14. 
above. The first “type of few pycnidia” developed a copious aerial — 
mycelium of loose floccose nature, extended regularly in all directions, — 
and was long devoid of pycnidia. When the pycnidia did form, 
they were few, large, and superficial (fig. 13). The second “type of 
many pycnidia’ had little or no aerial mycelium, all the mycelium 
being either immersed or of strict growth; was roughly circular in 
colony, not regularly so as in first type; and small, irregular, mostly 
immersed pycnidia were formed in myriads throughout the colony 
(fig. 14). These two types of colony appeared on the same plates 
which were inoculated with spores from the same pycnidium. They 
therefore developed in the same nutrient condition, humidity, tempera- — 
ture, etc. Depth of planting was not the cause of these difference — 
