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tions. The two noble Californian species already cited, though neither is 
remarkable for any peculiar consolidation of the powdery vesture con- 
cealing at first the disk of the young apothecium, furnish yet some inter- 
esting features, the examination of which is favoured by the large size of 
the fruit. In both of these, as seen in section, while the thick, brownish- 
black hypothecium of the proper exciple disappears, or at least loses its 
colour more or less completely above, enough is at times visible to 
exhibit, by contrast, the equally ascendant, interior, pale layer, which is 
in fact the only one (obscurely) reaching, or at least conditioning the 
thalline edge of the apothecium. We have here then, distinguishable by 
colour, if in no other way, something like a double envelope; and the 
structure is identical with what has elsewhere been noticed (Obs. Lich. 
l.c.) in other types. The white layer in the mature, turbinate fruit of 
A. tympanellum is, seen in section, not far from straight, as in many 
Calicia, or only a little lunate; but in the young conical state, which 
strikingly resembles A. Javanicum, it offers a distinctly ellipsoid outline, 
as in the latter, and resembles a delicate sack, enveloping the spore-mass. 
——Very little has occurred to me in authors, upon the point just con- 
sidered. Turner and Borrer (Lich. Brit. p. 122) describe the apothecium 
of Calicium as ‘in its earliest state closed with a very thin membrane 
(most conspicuous in C. tympanellum)” and cite also a passage of Acha- 
rius (LZ. U. p. 10) in which such a ‘“‘membrane, so extremely thin that it 
readily dissolves,” is attributed as well to ‘‘certain Arthoni@ and Calicia,” 
as to Solorina, Peltigera, and Nephroma. This last observation was 
vague; but the hinted structure in Calicium was recognized by Fries, 
who gave it at first (S. 0. V. p. 276) generical value; but passed it over, 
finally, in his Lichenographia. Montagne, however (Apercu Morph. dela 
Fam. des Lich. in Dict. Univ. d Hist. Nat., 1846) not only retained but 
extended it to the whole tribe, the apothecium of which is, according to 
him, ‘‘d’abord recouvert une membranule (velum) puis pulverulent ;” and 
is the latest authority in the matter with which I am acquainted. 
The variations in proportion, and shape (as seen in section) of the 
black and white excipular layers in different Calicieine types, have been 
already touched upon, and the attempt made to shew that even the extraor- 
dinary divergence (from our point of view) of Spherophorus, is counter- 
feited at least, by Acolium. But the normally nucleiform hypothecium of 
Spherophorus, by which the saccate outline of the white layer, as seen in 
Acolium Javanicum, is reversed, precludes at once any proper excipular 
features; and the veil is deficient. In A. leucampyz, on the other hand, 
so predominant does the white margin become, as wholly to overlay at 
length, and conceal the black one. Caliciwm also furnishes some inter- 
esting illustrations of this kind of diversity. In many species, the blackish 
hypothecium (at least in mature apothecia) almost excludes the white 
layer, which is observable (in section) only asanarrow, not far from straight 
line above. But in C. turbinatum the white layer, as seen in section, 
