SECTION OF VEGETABLE PATHOLOGY. 363 
The spores (Fig. 4, e, and Fig. 5) are about twice as long as broad, 
nearly eelineek, rounded at each end, contents granular and with- 
out nuclei, They sometimes project from the clusters of basidia in 
compact masses, held together by some substance which dissolves at 
once upon coming in contact witl¥water. 
Mingled with and surrounding the clusttrs of basidia are a few large 
dark-brown hyphe (Fig. 4, d), closely resembling the filaments of 
Vermicularia. They are much larger and longer than the basidia of 
the Glwosporiwm, are septate, and sometimes havea bulbous swell- 
ing at the level of the tops of the basidia ; below this point they are 
colorless. Sometimes the whole hypha is uncolored, butin this case 
it is usually smaller, indicating that itisnot mature. They are few 
in number as compared with the basidia, a dozen being a large num- 
ber for one cluster or pustule. These hyphz are not mentioned in 
any published account, but they were constant in the specimens ex- 
amined, although very scarcein some cases. The specimens were from 
the States previously mentioned and from Germany, and were named 
by Ellis, Farlow, and Trelease. They were also present in the same 
fungus on water-melon rind. 
Lafe history.—The spores falling upon the surface of the bean pod, 
send out a protuberance or germ tube on one side which presses close 
against the epidermis, and becomes transformed into a round, flat- 
tened body with a thick violet membrane. From this there soon 
protrudes a colorless hypha that bores through the outer wall of the 
epidermal cells and grows within them into a convoluted mycelium 
ce fills their cavities* and extends rapidly downwards and later- 
ally. 
In its healthy state the bean pod is composed of two well-marked 
layers of tissue with a line between. The outer (exocarp, Fig. 2, 0) 
is the firmer and more compact, and is generally of about the same 
thickness throughout the pod. The inner (endocarp, Fig. 2, c) is 
composed of larger and thinner walled cells, and is not continuous. 
If the beans are fully developed it is quite absent along their length, 
and very thin even in the intervals between them; but if the beans 
are not well-grown it is very thick, and in the intervals may fill all 
the space within the outer layer. It is accordingly thick in pods 
where the fungus has checked the growth of the bean. 
After leaving the epidermal cells the mycelium penetrates the 
walls of the cells beneath it, their contents and walls almost imme- 
diately become discolored, and in the exocarp the cells collapse, form- 
ing an almost solid mass of cell walls and mycelium (Fig. 2, a), In 
the endocarp the cells do not collapse at once, but the mycelium grows 
in them luxuriantly, almost filling their cavities; from here it pen- 
etrates to the bean itself, and may even form spores and basidia be- 
tween the testa and embryo. 
The exocarp shrinks into a mere line and sometimes separates from 
the endocarp like the skin of a blister. Usually, however, the two 
layers remain connected, and the whole spot sinks in (Figs. 2 and 3). 
The mycelium that is in the epidermal cells in the center of the , 
spot soon forms basidia which rupture the epidermis at points, form- 
ing pustules (Fig. 4); these pustules are so numerous in the older 
spots that they coalesce and are lost sight of, so that the surface is 
nearly or quite covered with a mass of basidia. The pustules are 
just visible to the naked eye, and sometimes have a dark-brown color, 
*Sorauer, Pflanzenkrankheiten. 
