DR. LINDSAY ON WEST-GREENLAND LICHENS. 337 
Tips of paraphyses deep brown and granular, their outline irregular. Asci and hymenial 
gelatine deep blue with iodine. Asci 8-spored, 0018" long and :0006” broad. Sporidia 
simple, oblong-ellipsoid (as in Lecanora subfusca), 0003" long and :00022" broad. 
Several forms of the plant occur, including opaca, Ach., and feracissima, Th. Fries. 
The Placodium ehrysoleucum of Dickie, from Davis Straits, east side, collected by Taylor, 
is quite the Greenland S. chrysoleuca, growing apparently in larger and compound patches. 
The spermogonia of chrysoleuca have already been described and figured in my “Mem. 
Spermog.' (pp. 259, 260, plate xv. figs. 15-17). 
In S. chrysoleuca and its var. opaca (= Parmelia rubina, vars. chrysoleuca and opaca) 
of Schærer, Exs. nos. 345, 346, the sporidia are the same as in the Greenland plant, 
ellipsoid, simple, colourless, 00033" to :0004.1” long and :00016” to :00020” broad. The 
asci are 8-spored, :00013" to :00016" long, and -0005" to :0006” broad. The paraphyses 
are discrete, their tips yellow or brownish-green. 
. In var. peltata, Fr.* (Nyl. Scand. p. 131, and Exs.), the sporidia are simple, ellipsoid 
to oval, colourless, 00033" long and :00020" broad. Asci blue with iodine, :0013” to 
*0016" long and 0005" broad. The epithecium is black-mottled with Phacopsis clemens, 
Tul.+ ; while the thallus is the site of other black, punctiform or papillæform verrucarioid 
parasites, associated with and externally resembling the spermogonia of chrysoleuca. 
These parasites include the Spheria described by Nylander (Scand. p. 133) as parasitic 
on the thallus of S. saxicola, which consists of minute, black, punctiform, immersed con- 
eeptacles containing fusiform colourless sporidia, associated with spermogonia, also 
black and punctiform, containing minute, straight spermatia. The thallus of chrysoleuca 
appears also to be the site of a parasitic Celidium (Tul. Mém. p. 125), by which it is 
rendered black-maculate. 
- 9. S. saxicola, Poll. Jakobshavn; Godhavn. Some of its forms (e. y. on Disco Island) 
are athalline, or nearly so, and are undistinguishable from Lecanora polytropa. The apo- 
thecia, asci, and sporidia are the same in the Squamaria and Lecanora. The apothecia are 
frequently very large, from being compound or confluent, irregular in outline and surface, 
immarginate, generally more or less convex and pulvinate. The sporidia, asci, and para- 
pliyses are also identical with those of S. chrysoleuca. The normal apothecia are small, 
crowded, with a thalline, thin exciple. A variety in the Kew Herbarium, from Cape York 
(Lyall, 1852), oceurs on the old weathered vertebræ of whales. 
The apothecia of Norwegian specimens collected by myself about Jerkin (Dovrefjeld, 
4600 feet, in August 1857) are the sité of a parasite, which unfortunately exhibits 
no structure. In the young state the disk is mottled over with very minute, round, 
blackish-brown spots. These gradually increase in size, coalesce, and cover the whole 
disk. The margin also becomes involved; and finally the whole apothecium (disk 
and exciple) become black and granular, resembling the black degenerate apothecium 
of some Lecidee (e. g. L. parasema). The parasite destroys at length not only the exciple 
but the disk, and thereby the whole general form of the apothecium; the disk becomes 
* This and certain other forms, Nylander appears (Scand. p. 131) to refer to S. melanophthalma, Ram.,—probably 
one of the many instances that abound in Nylander's works of excessive and unnecessary elaboration ! 
+ Referred to the genus Arthonia by Th. Fries (L. Spitsberg. p. 46); and to Conida by Körber (Parerga, p. 458). 
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