LINDSAY, ON LECIDEA LUGUBRIS. 
183 
bundles of thec^, — the amylaceous substance producing tbe 
reaction being probably a gummy intercellular matter^ which 
cements the elements of the hymenium. While the paraphyses 
are somewhat vividly^ and the thecse are slightly, tinged blue 
by iodine, the protoplasm and spores acquire a deep shade of 
yellow. Hence a section of the hymenium, to Avhich iodine 
has been added, is, under the microscope, perhaps even a 
more beautiful object than a section of the same hymenium 
in its natural state. The thecae, in the majority of cases, 
disappear after rupture and escape of their contents. But^ 
in some cases, the spores become shrivelled and aborted, and 
then carry with them the thecae as caudate appendages or 
tails. Sometimes, but rarely, the thecse present bulgings 
opposite individual spores, as if the walls were very thin and 
easily distended by unusually large spores. Such bulgings 
may occur opposite every spore, or only opposite one or two 
in a theca ; and such thecse have more or less of a moniliform 
character. The thecse appear to be developed with amazing 
rapidity, young ones shooting upwards from the hypothecium 
as old ones become ruptured and decay. May we not accept 
this fecundity of the hypothecium, this great number of 
thecse, and consequently of spores, as a beautiful instance of 
design in an alpine species, to obviate the counteracting 
influences of extreme cold and atmospheric vicissitudes ? 
The 2^araphyses, I have already stated, are about equal in 
length to the thecse, but they appear to vary somewhat in 
size. Hence one great reason, probably, of the fact that the 
apices of the paraphyses en masse are not so smooth or even 
as in the majority of lichens, but are irregular, appearing 
here and there between or above the apices of the thecse. 
They also appear to be fewer in number, compared with 
the number of the thecse, than in most lichens ; they are 
collected in bundles, which are sparingly scattered between 
the groups of thecse, and by which they look as if compressed. 
The apices are knobbed ; that is, they terminate in irregular 
wart- or knob-like cells of a deep indigo-blue colour. This 
colour of the terminal cellules, or articulations of the 
paraphyses, is the cause or source of the deep tint of the 
upper surface of the hymenium. The filaments of the 
paraphyses are delicate and wavy, and form a somewhat lax 
network en masse. 
The spores are about g/y^ inch in diameter. They are 
regularly globose, having a globular pale yellow nucleus_, 
between which and the cell- wall there is an interspace forming 
a hyaline distinct margin. Korber says the spore altogether is 
hyaline and colourless : this I cannot corroborate. The nucleus 
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