164 lichenes. [Spiloma. 



6. L. virescens, Sm. (dull-green Lepraria); crust filmy grey- 

 ish, sporules rather large subgelatinous deep green greyish 

 when dry collected into a thickish crustaceous mass. Turn, and 

 Borr. Lich. Br. p. 17. E. Bot. t. 2149. 



Trunks of old trees, principally Elm, in Sussex, Surry, Suffolk and 

 Norfolk ; generally near the ground. 



7. L. cinereo-suJphurea, Ach. (yellow-grey Lepraria); very 

 thin submembranaceous whitish the surface scattered over 

 with very minute aggregated granules greenish-yellow at first 

 afterwards cinereous. Ach. Syn. p. 330. Grew Fl. Edin. 

 p. 352. 



On the trunks of Scotch Firs, near Edinburgh, Dr. Greville. 



8. L. Jolithus, Ach. ? (violet-scented Lepraria); crust filmy 

 greyish, sporules extremely minute very red collected into a 

 thin even powdery mass. Turn, and Borr. Lich. Br. p. 19. 

 E. Bot. t. 2471. — L. rubens, Ach. Syn. p. 331 Byssus Joli- 

 thus, Linn. Sp. Pip. 1638 ? 



On hoarded buildings, old pales, and trunks of trees ; on rocks in 

 mountainous countries, sometimes on walls. — This plant is no less re- 

 markable for its colour, than for the violet odour which it yields on being 

 rubbed, and which remains with the plant long after it has been dried. — 

 Under Byssus Jolithus, two plants have been described, one filamentous, 

 the other pulverulent. The latter is our Lepraria ; the former is the 

 Chroolepus Jolithus of Ag. Sysl.Alg. p. 34 ; nearly allied to the Chr. Uchen- 

 icola of the same author, Conferva lichenicola, E. Bot. t. 1609. 



9. L. nigra, Turn, and Borr. (black Lepraria); crust filmy 

 greyish, sporules extremely minute black collected into a con- 

 tinuous thin even powdery mass. Turn, and Borr. Lich. Br. 

 p. 21. E. Bot. t. 2409. 



On squared timber. It forms large ink-like stains on the square tops 

 of posts and other timber. 



10. Spiloma. Ach. Spiloma. 



Thallus crustaceous, spreading, adnate, uniform. Apothecia 

 none. Sporules naked, coloured, collected into compact tumid 

 masses. — Name; miXa/ax, scattered spots ; from the appearance 

 of the fructifications. — " The transition" say Messrs. Turner 

 and Borrer (to whom we are indebted for all that is most valu- 

 able respecting this Genus) "from the Leprarice to the Spilomata, 

 is easy and simple ; a single step, and that a short one, seems 

 sufficient to lead us from the propagula (sporules) of the former, 

 scattered indiscriminately and constituting altogether what 

 appears to be a barren crust, to those of the latter, collected in- 

 deed here and there into little clusters, called pulvimdi, but, at 

 the same time, destitute of any integument or even margin, and 

 wholly simple in their construction ; except that in some species 

 may be discerned, by accurate observation, a small fleshy disk ; 

 which probably would be found to exist equally in all, did not 



