PAPERS ON BOTANY 225 
EXPLANATION OF PLATE 1 
Figs. 1, 2, 3, 4, 5. Diagrams of cross sections of apples showing the 
depth to which the fungus penetrates the tissue. 
Fig. 6. Tissue of diseased portion, showing mycelium and starch 
grains. 
Fig. 7. Tissue of healthy portion showing cells—no starch grains. 
Fig. 8. Chain of conidia from conidiophores; also a chain develop- 
ing laterally from a spore. 
Figs. 9, 9a, 9b. Spore with different lengths of beak. 
Fig. 10. Spore with small spore developing from end of a long beak, 
Fig. 11. Old spore showing round instead of angular cells. 
Fig. 12. Mature spore beginning to germinate. 
Fig. 13. Typical long beaked spores. 
Fig. 14. Mycelium from corn meal agar, showing the mature part 
and conidiophores dark and younger part light. 
Fig. 15. Aerial mycelium, showing size as compared with internal 
mycelium. Note enlarged cells. 
The conidia are borne in great numbers on the end of the 
conidiophores. It is difficult to determine how they are borne, 
as there is a sticky substance which holds them together in 
large masses which vary greatly in size and shape. These 
masses are at first greenish, but later almost invariably be- 
come black. 
The individual spores are elliptical to ovate and may or may 
not be pointed at the ends (Plate IV., Fig. 3). In size they 
vary from 5.4 by 2.7 microns to 9 by 3.6 microns. Spores in 
a hanging drop of distilled water showed a germination of 
about 50 per cent in 9 hours (Plate IV. Fig. 4). Ina hanging 
drop of cornmeal agar there was considerable growth in 12 
hours. (Fig. 5). 
CULTURES 
On cornmeal agar this fungus produced a very characteristic 
colony. As the colony developed there was an abundance of 
white flocculent, aerial mycelium. This partially disappeared 
when the spores began to form. The spore masses were gen- 
erally produced in concentric distinct rings. These rings were 
at first white but they later darkened, sometimes becoming 
green, and then black. There seemed to be some variation in 
color even when the fungus was grown on the same medium 
and under the same conditions. The spore clusters were very 
