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11 
pleasure. No words can adequately express their character, and 
to be enjoyed they must be actually and carefully examined. 
In thus briefly sketching some of the forms of crustaceous 
Lichens, one very attractive feature has been almost entirely passed 
over. Lichens owe a great deal of their beauty and interest to the 
forms and colours of their organs of reproduction. These are of 
two kinds, but one of them is so minute in size as seldom to be 
noticed. The larger one, which botanists call an afothecitum, is the 
organ in which the spores—bodies representing the seeds of 
flowering plants—are elaborated. The apothecia vary to a much 
greater extent than the thalli; though their external differences are 
few in comparison with their internal. 
All the examples I have chosen as illustrative of the forms and 
variations of the crustaceous thallus have been taken from one 
genus. But exactly similar forms occur in other genera, the generic 
characters being found in the structure of the fruit. 
Thus the difference which separates the two genera, Zecidea and 
Lecanora, is the kind of border which surrounds the apothecia; in 
Lecanora this border is composed of the thalline substance, in 
Lecidea it is formed of a different tissue. 
Very interesting apothecia are those characteristic of the Verru- 
carie. Here each fruit is a little black or coloured cone having a 
minute pore at the summit through which, when mature, the spores 
are emitted. The stalked apothecia of the Ca/icia are extremely 
peculiar, looking like Lilliputian pins or nails, and their dusty 
heads are usually crowded with a brown mass made up of thousands 
of spores. 
But perhaps the strangest and most striking of all lichen-fruits are 
those found in certain Graphids, or letter-lichens. We have several 
species of them in Westmorland, some growing on trees, others on 
stone. The name given to this tribe is derived from the shape 
of the apothecia, which instead of being round, as in most genera, 
are long and narrow, sometimes simple, but often forked at various 
angles. A branch of a tree on which these plants have located 
_ themselves appears as if written over with characters having a 
wonderful resemblance to Eastern writing—Hebrew, Arabic, or 
