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C. W. EDGERTON 
is no question, however, regarding the identity of this fungus. The 
perithecia, asci, and ascospores cannot be told in any way from the 
same structures in other Gloeosporium cultures. Furthermore there 
were typical conidia along with the perithecia on the morning glory 
stem from which the cultures were made. 
The presence of two strains was first recognized in the culture from 
the Cottonwood. Plantings in petri dishes often showed a colony 
development like the one illustrated in Plate I, fig. i. In the center 
there was a strict growth, black with perithecia, and generally some- 
what stellate in shape. Outside of this there was a floccose growth 
in which perithecia developed in masses in a manner similar to most 
described Glomerella cultures. Perithecia on the boundary line 
between these two different growths were always better developed 
than the perithecia in the black portion of the colony. The plate 
looked as if there were two fungi present and that the white one was 
a more rapid grower and had finally outgrown the other and confined 
it to the central region; and this was finally proven to be the case. 
Dilution cultures were made from the two portions of the plate and 
the two distinct forms of growth were isolated. Transfers made from 
colonies developing from single spores showed two distinct forms and 
these are the ones which are designated in this paper as the plus and 
minus strains. These have been studied on various culture media 
and under various conditions for several years. 
The plus strain grows well on all of the ordinary culture media and 
in most cases it develops an abundant growth of aerial, floccose 
mycelium of a white or light gray color (upper right and lower left 
quarters, Plate II, fig. i). Perithecia usually develop when grown on a 
good medium such as bean or oat juice agar and they always form in 
raised masses or nodules similar to the perithecia of other described 
species of Glomerella. The asci (fig. ib) and ascospores are always 
well developed in the perithecia. This strain grows more rapidly than 
the other and when the two are together, it usually confines the latter 
to the central region of the colony (Plate I, fig. i). 
The minus strain also grows well on most media but produces 
scarcely any aerial mycelium. The perithecia are produced in great 
abundance in and on the surface of the culture medium (upper left and 
lower right quarters, Plate II, fig. i), generally single though occa- 
sionally in twos or threes. The abundance of perithecia generally 
gives the culture a black color. On ordinary culture media as potato 
