312 DR. LINDSAY ON WEST-GREENLAND LICHENS. 
folioles are frequently very thick—and when moist, semi-cartilaginous—when dry, brittle. 
They are densely arranged, and form flat tufts. These brown microphylline states 
resemble the thallus of Lecidea (Psora) ostreata, Hffm. The lobes are fringed with 
dark brown or blackish-brown tubercles, resembling spermogonia in site and shape; 
sometimes these tubercles are seated on the surface of small digitate prolongations 
of the lobes. They are seen only under moisture, and even then with diffieulty, by 
reason of their minuteness. Their envelope is of such tenuity that it nearly loses co- 
hesion under pressure of the microscope glass: it is composed of brown irregular cells, 
normally spherical. The contents are myriads of corpuscles, resembling the stylospores 
of Peltigera, but pale green, and shaded, not distinctly granular, mostly spherical, 
varying little in size and form, with a diameter of -00015” to :00020", sometimes 
adhering in twos and having then a resemblance to figure-8-shaped sporidia. 
In the Kew Herbarium, certain specimens, labelled cervicornis, are really referable, I 
think, to pyridata, degenerans, gracilis, and verticillata *, while I refer no. 754 Mougeot 
and Nestler's Exs. to pyaidata. 
3. C. squamosa, Hffm.—Jakobshavn. Various forms; sometimes corticolous (on birch). 
Its spermogonia are those typical of the genus, terminal, deep brown, barrel-shaped ; 
the ostiole spherical and distinct under the lens. Spermatia straight, in myriads, on 
digitate sterigmata. \ | 
Various forms of squamosa and gracilis are confounded with each other in the Kew 
Herbarium. | 
4. C. gracilis, L.—Jakobshavn ; Illartlek glacier. Various states, mostly deformed. 
Colour varies from white or pale, through brown, to deep ash-grey or black. Bases 
of podetia, which are immersed in moss (apparently Rhacomitrium lamuginosum), are 
often or constantly quite black. Sometimes the podetia are black from base to apex, 
or the upper portion is dark brown. These dark forms are covered sparingly with 
white or very pale green, irregular, tumid phyllocladia, which are very conspicuous on 
the dark podetia. Deformed scyphi sometimes give off secondary podetia. ` The phyllo- 
cladia of the podetia (in some forms only) give the beautiful lemon-yellow of cervicornis 
with potash. A pale, white and green-spotted form, growing in the shade of Cetraria 
cucullata, shows no reaction. Sometimes the most deformed conditions are the most 
elegant. Podetia are sometimes studded over, about their tips, with a very minute, 
black, punctiform parasite, which has the structure of a Torula +, consisting of chains of 
oblong, brown, spore-like cellules. The parasite is seen with difficulty even under the 
lens; itis to be found equally on fertile and sterile podetia. On one of the podetia I 
also met with a brown, 2-locular sporidium, having the characters of the sporidia of 
Buellia or Rinodina; obviously it was a wanderer, and could have no relation to the 
Cladonia or its parasite. I have repeatedly met with such errant sporidia in different 
lichens $. Occasionally their presence may, to the student, be the source of consider- 
able confusion. ; 
|. * Coemans regards cervicornis as a macrophylline var. of C. verticillata, Fr. 
+ The same Torula apparently, which is probably T. lichenicola, Linds., occurs also on Lecanora tartarea and 
L. oculata (q. v.). t Vide Lecidea petræa, n. 5. 
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