236 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
tissue. The interior of the spermogone contains much mucilage. The spermatia 
are rod-shaped, thickish throughout, with obtuse ends—about ath to th long. 
They are thrown off from the ends and sides of very irregular, ramose sterigmata, 
which consist of several linear, longish articulations—very beautiful and distinct. 
The cellular tissue, of which the spermogonal envelope is composed, is of a very 
pale brown. Apothecia are abundant. 
Specimen 2.—ScH&RER exs. 370 (sub a. corticola a. glabra); on trees in open 
places ; Switzerland. The spermogones occur, on the right-hand specimen in my 
copy, as deep olive-coloured or brown punctiform bodies,—wholly immersed,— 
scattered about the edges of the lobes. The thallus, as in the former case, and 
indeed in all cases, requires to be moistened before the extremely indistinct sper- 
mogones can be seen. 
Specimen 3.—SCHERER exs. 372 (sub @. saxicola, a. glabra); on stones in 
alpine localities; Switzerland. The spermogones are here scattered over the sur- 
face of the thallus as minute black or brown bodies, sometimes punctiform, some- 
times papilleform. The spermatia are about sath to auth long, rod-shaped, 
studded on the apices and sides of articulated sterigmata. 
Specimen 4.—Var. aquiloides mihi. From Miss Hutcuins, 1810; no habitat 
given, but probably from Ireland; in Herb. Hooker, Kew; and also, from the 
same lady, in Herb. Carroll. The whole plant so closely resembles in general 
aspect Physcia aquila, that I propose designating it as var. aquiloides. It is 
generally only distinguishable by its apothecia and spores, which are those of 
P. oliwvacea, simple, oval, and colourless; those of P. aquila being brown and 1-sep- 
tate. ‘The laciniz are pale, narrow, and convex, studded over with minute papil- 
leform spermogones, resembling those of P. aquila, chiefly old, and containing no 
free spermatia. 
Species 24. P. stygia, Ach., 
A native of Europe and Northern America. 
Specimen 1.—Summit of Ben Nevis, August 1856, W.L.L. The plant is abun- 
dant in this locality, bearing fine apothecia. The lacinie are narrow, convex, and 
pitchy-black ; they are covered over with black minute papillee or perforations, 
the latter having generally a sub-prominent black edge. These papillee mark 
young spermogones with imperceptible ostioles; the perforations are the patent 
ostioles of old spermogones, generally very indistinct on the dark-coloured thallus. 
The peripheral lacinize are sometimes pale; in which event the plant has a close 
resemblance to var. stygioides of P. encausta, as it occurs on the summit of Cairn- 
gorm. 
Specimen 2.—Summit of Morchone, Braemar, August 1856, W. L. L.; with 
apothecia. The spermogones are scattered abundantly over the convexities, and — 
towards the tips of the lacinize, as minute black papilla. The older spermogones — 

