
OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 237 
are marked by large, gaping ostioles, usually more or less round in outline, hav- 
ing black, turgid, ring-like borders. The spermatia are rod-shaped, about goth 
long, seated on the apices and sides of very irregular, delicate sterigmata, the 
articulations of which are short, roundish cells. Associated with the sterigmata 
are numerous elongated branching filaments, also articulated or septate, which 
project into and occupy the cavity of the spermogone, as in P. physodes, P. saxa- 
tilis, &e. 
Specimen 3.—ScHARER exs. 255 (sub Cetraria stygia, a. latior) ; with apothecia ; 
on stones in the higher Alps, Switzerland. The lacinize are studded over with 
minute perforations, which are the ostioles of old spermogones, containing no free 
spermatia. 
Species 25. P. Fahlunensis, Ach., 
A native of the alpine or frigid portions of Europe, America, and Asia. In this 
and the following species the spermogones are marginal,—forming a sort of den-. 
ticulate fringe, as in Platysma. 
Specimen 1.—Summit of Cairngorm, August 1856, W.L.L. The spermogones 
abundantly fringe the crisped, curled margins of the flat, linear, pitchy-black 
lacinize, as deep-brown, minute, round warts. They resemble the spermogones of 
Platysma ciliare, but are generally not so closely aggregated. The spermatia are 
very minute, ellipsoid, about ;th long, immersed in an abundant mucilage. The 
sterigmata are articulated, but very delicate and indistinct. 
Specimen 2.—On rocks, Carlowrie, 1843 ; coll. Garpiner, of Dundee; in Herb. 
Royal Botanic Garden, Edinburgh. There are no apothecia; but the spermo- 
gones are very abundant and distinct. They are barrel-shaped and black, fringing 
the margins of the lacinize like teeth, and precisely resembling the spermogones 
of P. ciliare. They are seated also frequently on the flat surface of the lacinicz, 
near their ends, growing upwards at right angles to the thalline surface. 
Specimen 3.—ScHERER exs. 373 (sub a. vulgaris, a. major), and 374 (sub 
a. ctulgaris, b. minor); on micaceous rocks in the Alps. The spermogones are 
precisely as in Nos. 1 and 2; the spermatia are rod-shaped and minute, and the 
sterigmata shortish and of a few articulations. 
SPECIES 26. P. tristis, Web., 
A native of Europe and North America. As in the preceding species, the sper- 
mogones occur only on the margins of the flat, linear, erect lacinize. In the young 
state, they are inconspicuous small black cones or warts; in the old state, they 
are much more easily recognised by the large, gaping ostioles with turgid, black 
borders. The oldest spermogones are usually found lowest down on the thalline 
’ lacinize; hence the spermogones about the tips are generally papilleeform, young, 
and full of free spermatia, while those about the base are perforate, empty, 
VOL. XXII. PART 1. 3 P 
