PYCNIDES OF CRUSTACEOUS LICHENS. . 251 
The spermogones are minute brown or black, punctiform, seated on separate thalline 
wartlets, scarcely visible under the lens even when moistened. The spermatia are small, 
delicate, and rod-shaped, on indistinct, but apparently thickish, arthrosterigmata, as in 
No. 5. ' 
Specimen 7. Var. epipolia, Ach. (Mudd, Brit. Lich. p. 218). In the Schwarzwald, 
Hochstetter; Scheer. Exs. No. 230, sub Lecidea calcaria, var. cretacea. The spermogones 
are small black points, immersed or semiimmersed, scattered externally to the apothecia. 
The envelope is of pale-brown cellular tissue; the spermatia acicular, about 57575 long, 
on sterigmata digitately divided below as in Abrothallus oxysporus, and very irregular 
in outline. 
Species 14. L. petra, Flot. | 
Specimen 1. On flint: Leight. Exs. No. 184. Associated with L. atro-alba, var. atro- 
albella, Nyl. Spermogones are small black points, seated on the sterile, dark-grey or 
brownish thalline areolæ. Spermatia suboblong, subatomic in size. Sterigmata longish, 
linear, branching from the base as in Ramalina, sometimes also consisting of two or 
more articulations; they vary much in length, but are always very slender or filiform. 
The basal cellular tissue is scarcely coloured. 
Specimen 2. Var. @deri, Ach. (Mudd, Brit. Lich. p. 220), which seems to me a mere 
state, with a rusty-red thallus from coloration with peroxide of iron, analogous to similar 
conditions of L. contigua. On basalt, Lounsdale, Cleveland, Yorkshire: Leight. Exs. 
No. 187, sub Lecidea deri. The spermogones are externally exactly as in the preceding 
(No. 1); but the spermatia are smaller in all their dimensions, while the sterigmata are 
also very short, and comparatively simple. 
Species 15. L. DISCIFORMIS, Fr. 
Specimen 1. On trees, hills east of Glen Callater, Braemar, Aug. 1856: W. L. L. 
Associated with L. parasema, whose thallus differs in being yellowish-green and smooth, 
while that of L. disciformis is white, and granulate or warted. Spermogones abound as 
black points, crowning some of the thalline wartlets. Spermatia are rod-shaped. Sterig- 
mata consist of a few linear, irregular artieulations. Basal cellular tissue pale brown. 
The thallus, sporidia, and spermatia here equally and easily separate disciformis from 
parasema. 
Specimen 2. On trees, Glen Nevis, Aug. 1856: W. L. I. Spermogones are abundant 
and distinct, scattered, chiefly externally to the region of the apothecia, as round, minute, 
black dots crowning the wartlets of the whitish thallus. Their cavity appears to be 
simple; the spermatia rod-shaped, about 3345 long; the sterigmata longish, articulated, 
and ramose, but indistinct. 
Specimen 3. On trees, Fort Augustus, Aug. 1856: W. L. L. Associated with Z. 
parasema, and Lecanora subfusca and varia. The spermogones are here pale or brown 
dots, perched on irregular, compound, white thalline tubercles or papillæ, containing 
acicular spermatia on sterigmata that consist of a few narrow, delicate articulations. 
Specimen 4. On old bark, Killarney: Carroll. The apothecia are old and degenerate, 
