346 DR. LINDSAY ON WEST-GREENLAND LICHENS. 
intermediate between the true Lecanore and the Pertusarie. Whatever its position 
in classification, the plant illustrates the close affinity between these two great genera. 
5. L. ventosa, Ach.—On granitic rocks about Jakobshavn; not common. Apothecia 
and spermogonia abundant, as well as the parasitie Spheria ventosaria, Linds.* The 
thallus is of an unusually vivid green, a character, however, which is common to all 
northern or arctic lichens with a greenish thallus. The spermogonia and the Spheria 
are externally alike, the perithecia of both consisting of black, irregular warts ; but their 
contents at once distinguish them. The Greenland Spheria has polysporous asci, 0015" 
long and :00045" broad, the sporidia being ellipsoid, olive or brown, 2-locular, sometimes 
figure-8-shaped, and very minute, :00022" long and :00009" broad. 
In specimens of L. ventosa, collected in the Braemar Highlands, in August 1856, I very 
frequently met with the Spheria, but rarely with the spermogonia, which are usually 
externally undistinguishable from the parasite. The spermogonia, however, were abun- 
dant in a specimen from Morchone, as irregular, flattish, longish, conspicuous, elevated 
warts, seated on individual areole of the thallus, their surface black, or bluish-black, 
pierced by several irregular blacker openings or ostioles. The spermatia were numerous, 
as straight rods, about 00025" long, arising from the apices of delicate, linear, irregularly 
digitate, and sometimes bulging sterigmata, subsimple or consisting of only a few articu- 
lations. Interspersed with these spermogonia were a number of black, papillæform 
perithecia, much more like ordinary spermogonia, but which really belonged to the 
parasitie S. ventosaria. 
On another specimen, bearing normal apothecia (from the summit of Lochnagar), I 
found spermogonia abundant, external to the region of the thallus occupied by the 
apothecia. Here, again, they occurred as large, irregular, prominent warts, of a darker 
green than the thalline verrucæ upon which they were seated, their apices covered with 
irregular, black, or bluish-black ostioles, indicating compound perithecia. These ostioles 
are the only external distinguishing feature, as they are never seen in the Spheria. 
6. L. subfusca, L.—Jakobshavn, on twigs of birch; a form with very’ small apothecia, 
- very sparingly distributed. Muscicolous forms (= epibrya, Ach.) are more common. 
In Britain, L. subfusca is very frequently the seat of various parasitic Fungi or Lichenst. 
Of these by far the most common I have met with is, especially in Irish specimens, 
Torula lichenicola, Linds., which occurs both on its apothecia and thallus. 
7. L. frustulosa, Dicks.—Jakobshavn. Its white, tartareous thallus, of pulviniform 
areolæ, gives a beautiful lemon-yellow reaction with potash, a reaction that is common, 
however, on white, tartareous thalli, both in Zecanora and Lecidea. Hymenial gela- 
tine beautiful pale blue with iodine. Tips of paraphyses agglutinate and pale brown. 
Sporidia simple, oval, or broadly ellipsoid, about ‘0006 long and :00022" broad ; some- 
times with granular or muco-granular contents; frequently exhibiting 1, 2, or 3 large, 
prominent nuclei. | | 
* Described in the author's * New Zealand Lichens and Fungi" Trans. Royal Society of Edinburgh, vol. xxiv. 
p. 439. 
t £.9,:—1, Spheria apotheciorum, Mass. ; 2. S. epicymatia, Wallr. ; 3. Arthonia varians, Dav. ; 4. Pharcidia con- 
gesta, Kórb.; 5. Lecidea parasitica, Flk. 
