MOXOGRAni OF TUE LABOULBENIACE.E. 239 
which under abnormal conditions may be replaced by or associated witli U pically flla- 
itous growths simihirly derived from the basal cell?'. 
In very rare instances individuals are met ^ith in wliicli a (3 
>- 
pendage, in a normally bisexual form, is substituted for the fem;i1.^ orgnn, the 
substitution being accompanied by a great increase in tlie number of anthci-idia pro- 
duced. An abnormal male individual of this kind is rc'j)rcsentc(l in riatc H, fig. 7, the 
two appendages being in general normal even to the formation of the blackened in- 
4 
sertion cells. 
We have seen that in general the spores arc discharged in pairs, and that, as a 
rule, and sometimes invariably, they adhere to the host and develop side by side. It 
fact which may possibly 
the derivation of 
dioecious from the monoecious forms, that in certain instances one member of llie spore 
pair may normally, or not infrequently, become atrophied, or produce a smaller and 
weaker individual than the other. In the case of Lahonlham wjfafa the atrophy of 
one of the spores, after it has reached an inconsiderable development, seems to be an 
invariable rule, as far as I have had an opportunity for observation, and groups of 
this species, when detached with a portion of the Integument on which they are 
growing, show the condition of things represented In fig. 5, Plate 111, the atrophy 
being apparent even at an early stage. 
' Kormal Variations. Like other groups of plants, the Laboulbcniaceas are subject 
to normal variations in form, size, color, etc., which are partly inherent and partly 
due to the action of external causes. In individuals growing under identical con- 
ditions, the variations are comparatively slight, and are expressed by inconsiderable 
or variations in the relative development of different parts, 
irences in color, which are, however, in general, due to the 
d i iTe 
often coupled with diff 
-y 
of individuals. Forms, for instance, which, when } 
arc sufficiently advanced to d 
o 
4 
hyaline or pale straw-color, 
m 
ay become, as their age increases, dark amber-brown or suffused, wholly 
blackish or smokv 
Among 
the external causes which influence variation, the most important ar 
a 
ted with the character of 
1 
and the position in which the p 
site grows up 
P 
dark or black 
it. The color of the host, for example, often influences that of tl 
; species being sometimes very dark or nearly opaque on hosts wii 
pellucid, or nearly hyaline, on hosts of 
O 
hter color, such dilTerences in color being independent of dilTcrences in the 
dividual 
