DR. LINDSAY ON WEST-GREENLAND LICHENS. 357 
var. adglutinata, and to Lecidea adglutinata of Nylander's Exs. The.latter, however, has 
simple sporidia, while the colour of the thallus is also very different. 
9. L. alpicola, Sch.—Jakobshavn. On gneiss, associated with L. geographica, L., both 
in fruit. The former has paler areolæ, generally also subconvex or pulviniform. The 
apothecia also are more convex and more frequently seated on, as well as between, the 
areolæ. The sporidia of alpicola are here regularly 2-locular, olive or brown, oblong or 
oval, sometimes figure-8-shaped or soleæform, or assuming various irregularities of out- 
line and size. Size about :0006” to :0009” long and :0003" to :0004” broad. In the 
young state, occasionally simple and granular, or full of nucleiform corpuscles. In age, 
the sporidia frequently split at the septum, the halves occurring on the field of the 
mieroscope intermixed with full-sized sporidia. 
Th. Fries (L. Arct. p. 236) considers alpicola a variety of geographica; and in one 
sense he does so correctly, inasmuch as the 2-locular sporidia become in some cases muri- 
form ; that is, their characteristic form in alpicola passes into that supposed to be peculiar 
to geographica. But in the Greenland plant the sporidia are constantly 2-locular. Ina 
specimen of geographica on basalt, collected by myself on the hills above Balthayock, 
near Perth, in April 1858, besides sporidia of the ordinary (muriform) character, are 
others, apparently young ones, which are colourless, broadly ellipsoid, and 2-locular. 
If alpicola is to be associated with geographica, the same principle would require the 
association of atro-alba with petræa, and myriocarpa with disciformis. Such a procedure 
would reduce to a very large extent the present enormous number of Lecideæ, by enlar- 
ging, or adding to, the comprehensiveness of the definitions of * species," and degrading 
from the rank of species many Lecidee which at present hold this separate position in 
classification. Of the general principle involved in such a procedure, and of the consequent 
practice, I most thoroughly approve. But there are great difficulties in carrying the 
principle out in praetice, sometimes from the extreme variability of organs, sometimes 
from the unequal values in different genera of the same organs as specific characters. 
10. L. galbula, Ram. A sterile thallus (only), which Iassign to this species, occurs 
in the present collection. It is of a much more brilliant green than that of L. geogra- 
phica, and has more convex or pulviniform areole, Only sometimes does this species, so 
called, exhibit the beautiful citrine yellow of Lecidea citrinella, L. lucida, Coniocybe 
Jurfuracea, or Evernia vulpina. The plant is not mentioned as a Greenland lichen 
by Th. Fries (L. Arct. p. 176, where it is described as Catolechia pulchella, Schrad. ). 
It seems to me referable to the section Buellia, and undeserving a separate generic 
name. 
ll. L. fusco-atra, L.—Jakobshavn. On gneiss; apothecia abundant; associated and 
apt to be confounded with L. atro-alba, requiring microscopical examination for its di- 
stinction. The thalline areolæ are sometimes small, subconvex, and pale, resembling 
those of atro-alba. In the young state they are sometimes sparsely scattered, and their 
convexity is such that they have the character externally of certain immarginate apo- 
thecia. The disk of the apothecium is sometimes white-pruinose, as in L. abietina. 
In Europe, the thallus of fusco-atra is occasionally the seat of certain parasites, e. g. Fer- 
rurcaria gemmifera, Tayl. 
