DR. LINDSAY ON WEST-GREENLAND LICHENS. | 331 
and P. stellaris on the old thallus of various Umbilicarie. The forms of saratilis growing 
on U. vellea are microphylline, sterile, but dotted over with a black papillæform para- 
site, which exhibits no distinct (or normal) structure. Curiously, I met with no traces 
of Abrothallus* in Greenland. But the sphaerophoroid deformities ( before-mentioned) of 
sawatilis frequently resemble, in their globularity, the anamorphoses of thallus associated. 
with the growth of that peculiar pseudo-genus. 
2. P. arctica, Nyl.—Jakobshavn. On granitic or gneissóse rocks; sterile. When 
moistened, the thallus assumes an olive colour, like that of olivacea, some of whose forms 
the plant otherwise closely resembles. It has the character, so far, of a Norwegian speci- 
men of arctica, collected by me on the top of Sneehätten, Norway, in August, 1857, and 
determined by Nylander. But the Norwegian plant is blacker, especially centrally. In 
both the Greenland and Norwegian plant there are, especially centrally, erosions of the 
superficial or cortical layer of the thallus, exposing the white medullary tissue. I have 
seen no fertile specimen of Nylander's arctica (Synopsis, p. 394); but I doubt the 
propriety of its classification as a distinct species. It certainly does not belong to 
encausta, or alpicola t Th. Fries (Arct. p. 57), but probably to some of the puzzling 
broad-lobed or macrophylline forms of olivacea or fahlunensis. 
3. P. olivacea, L. All its forms are sterile. Sometimes there is a tendency to an isi- 
dioid condition of the centre of the thallus and margins of the laciniæ, its character then 
approaching exasperata. But the isidia are generally large and discrete warts. Some- 
times the thallus is curled up into spherical masses, resembling the similar anamorphoses 
of P. saxatilis and P. sinuosa. Some of its macrophylline forms resemble certain condi- 
tions of P. saxatilis and its var. omphalodes. The laciniæ, in such states of the plant, are 
fossulate, with subretuse ends; the colour is light olive, rendered much greener by mois- 
ture; the surface smooth and glossy. Microphylline forms, on the other hand, resemble 
Jahlunensis. 
4. P. fahlunensis, L. Like olivacea, saxatilis, arctica, and the majority at least of the 
Greenland Parmelie, I found it only sterile, occurring in various puzzling forms, differ- 
ing in colour and in the size and flatness of the laciniæ. Some of these forms resemble 
conditions, or possess certain characters, of saxatilis, omphalodes, and olivacea. Thus the 
plant is sometimes macrophylline, of lighter colour than usual, becoming greener when 
moistened ; the surface dull or glossy; the laciniæ terminating retusely, as in sazatilis, 
and similarly fossulate. There are several sterile Greenland Parmelie, which I am puzzled 
to refer either to omphalodes, olivacea, arctica, or fuhlunensis, combining, as they do, 
some of the characters of all these species or varieties. All the species or pseudo-species 
referred to frequently form very handsome, round, dark, conspicuous patches on. quartz- 
ose, granitic, or gneissose rocks and stones. Macrophylline and microphylline conditions 
of the same species are sometimes curiously associated. 
5. P. stygia, L.—Jakobshavn, in fruit; Illartlek Glacier. Thallus becomes deep olive- 
* A. Smithii occurs in Europe, both on P. sazatilis and var. omphalodes; and A. a on the type (Mono- 
graph of Abrothallus, pp. 35-38). 
+ The name P. arctiea, Th. Fries, in my * Lichen-Flora of Northern Europe" (Journal of Linnean Society, 
Botany, vol. ix. p. 409) is an error, as I find no such Parmelia in his * Lich. Arctoi.’ ae 
E 
