218 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
in Herb. Carroll. There are no apothecia; but old degenerate spermogones 
abound about the ends of the laciniz. They are brown, immersed, round, ellip- 
soid or lirellaeform, or still more irregular in form ; on free spermatia are seen. 
The colour of the thallus is white. Nova Scotia, 1784, in Herb. Menzies, Royal 
Botanic Garden, Edinburgh; has both apothecia and spermogones; as has also a 
specimen from Kollong, Khasia, India, temperate region, at an elevation of 5000 
feet ; coll. Drs Hooker and Tuos. THomson; in Herb. Hooker, Kew. 
Specimen 9.—Var. erratica mihi, Melbury Hill, near Shaftesbury, Dorsetshire, 
May 1857; coll. Sir WaLTer C. TREVELYAN of Wallington. This is a very curious, 
erratic, globular form, the thallus having become repeatedly curled inwards on 
itself, so as to assume the form of a small ball; it was found lying free or unat- 
tached on the ground, rolling before the wind on the downs of Melbury Hill. 
Specimens were submitted by Sir WaLTER TREVELYAN to the most distinguished 
British lichenologists, all of whom were puzzled in regard to its name and place 
in classification, and each of whom ascribed it to a different species. Sir W. 
Hooker referred it to P. sazatilis ;* the Rev. M. J. BerKELEY and the Rev. 
CHURCHILL BasineTton to P. stellaris ;* the Rev. W. A. Leicuton to P. sazatilis, 
of which he constituted it var. concentrica ;+ while I placed it provisionally under 
P. cesia.t This difficulty or dubiety arose from the absence of apothecia. Nor, 
when I first examined the plant, did I find any spermogones; but in specimens 
subsequently sent me by Sir WaLTER TREVELYAN, I have been successful in find- 
ing them in small quantity; and hence am now able to refer the plant to P. s¢nu- 
osa. Many specimens are very like P. perlata, and others like P. saxatilis. But 
the examination of a suite of specimens, in very different states, leads me to place 
it here; constituting it, as it deserves, into a distinct variety, to which I give, in 
allusion to its peculiar habit, the appellation erratzca. The thallus is smooth and 
glaucous; marginal soredia and marginal cilia are occasionally found on some 
specimens, and on some lobes. The spermogones are few, old, and scattered about 
the ends of the lacinize; they contain no free spermatia. Outwardly, they have all 
the characters of those of P. senuosa. In some specimens the plant is associated 
with spermogoniferous states of P. physodes, and has evidently been detached from 
the twigs of trees, which would appear to be its normal or usual habitat. 
Specimen 10.—Var. Caracensis (Parmelia Caracensis, Taylor), Caracas, South 
America; coll. J. Lrinpen, 1842, exs. No. 576 ; also Columbia, JamEson; both in 
Herb. Hooker, Kew. The spermogones are scattered about the ends of the lacinie, 
the young ones as punctiform, immersed, black bodies, the old ones as small black 
* Qardener’s Chronicle, Feb. 9, 1856, p. 84, and March 15, 1856, p. 172, Scottish Gardener, 
No. 3, p. 100, March 1856 (Proceedings of Botanical Society of Edinburgh). 
+ Leteuton’s Lich. Britannici exsicc. Fasc. 8, No. 232 (1856). 
+ Popular History of British Lichens, London, 1856, p. 211, e¢ seg. Monograph of the Genus 
Abrothallus, in Quarterly Journal of Microscopical Science, January 1857, p. 41. 

