Rev. W. A. Leighton on British Lichens. 11 



J. Ralfs, Esq. ! Rocks at Coachford, west of Cork, J. Carroll, 

 Esq.l 



This plant occurs in dense, entangled, decumbent masses, 

 loosely attached to the rocks. Filaments rather coarse, and of 

 a minute, tubercular, or scabrous appearance, dark brown, va- 

 riously and irregularly branched. When seen moistened under 

 the microscope, they are of an olive-brown colour ; the granula 

 gonima in the young branches and extremities of the branches 

 appear transversely arranged, very similarly to those of Spilo- 

 nema paradoocum ; but in the larger and older stems they are 

 more scattered and distant, and smaller in size, and are arranged 

 somewhat irregularly transversely, in heaps of several together. 

 The apothecia are immersed in subfusiform swollen portions of 

 the thallus, at a little distance from the extremities of the 

 branches, and are similar to those of Endocarpon, spherical, 

 with brownish perithecia. Paraphyses indistinct, mucilaginous. 

 Sporidia 8 in each ascus, oblong, elongated, shortly fusiform, 

 1 -septate, hyaline. Spermogonia in lateral prominences; sterig- 

 mata simple; spermatia straight, cylindrical. 



For the unravelling of the synonymy, see Bornet, /. c. 



Plate IV. fig. 12. Portion of older stem, magn. 330 times linear, 

 fig. 13. Sporidia, magn. 1200 times linear, 

 fig. 14. Spermatia and sterigmata, after Nylander. 



I possess a plant from Dr. Nylander, without any locality, 

 named Pilonema contextum, Nyl., which, from the general ap- 

 pearance and structure of the thallus, seems allied to the fore- 

 going. It grows in dense entangled csespitose masses, of a 

 blackish-brown colour. The filaments are very much branched, 

 and seem, when moistened under the microscope, to consist of 

 longitudinal series of small moniliform granula gonima immersed 

 in cellular tissue. There is no fructification on the specimen. 



Plate IV. fig. 14. Portion of thallus, magn. 330 times linear, 

 fig. 15. Granula gonima, magn. 1200 times linear. 



Racodium mpestre, Pers., of which I have a specimen from 

 Dr. Th. M. Fries, gathered at " Smolandia, Femsjo, 1851," 

 and which I have gathered on rocks at Sychnant, near Conway, 

 and on the High Rock, Bridgenorth, Shropshire, and have also 

 specimens from Llandrindod (Rev. T. Salwey), Leicestershire 

 (Rev. A. Bloxam), and Cleveland (Mr. W. Mudd), and which, 

 according to a specimen received from Dr. Guthnich, from the 

 collections of Schaerer, gathered at " Tete Noire/' and labelled 

 " Collema pannosum, Schaer. Enum. p. 248," would seem to be 

 included in that species by that author. Of this plant a fair 

 representation is given in Dillwyn's ' Confervas/ tab. 101, as 

 C. ebenea. Viewed under the microscope, it is found to consist 



