152 LICHENES. [Verrucaria. 



it growing. Yet the structure of the crust seems very different, as well 

 as the colour both of that part and the fructification." — The tuber- 

 cles are much more minute than those of any other British Verrucaria. 



13. V. leucocephala, Ach, (white-fruited Bark Verrucaria^); 

 crust between filmy and tartareous grey pruinose, apotliecia 

 largish prominent spherical or almost cylindrical brown covered 

 with white powder their apex at length bare. Borr. — Ach. 



Meth.p. 116. Borr. in E. Bot. Stippl. t. 2642./. 2 Pyrenula 



leucocepliala, Ach. Syn. p. 126. — Cyphelium leucocephalum, "Ach. 

 in Stockl. Trans, for 1817, p. 226. t.S.f. 7." — Sphccria leucoce- 

 pliala, Ehrh. and Pers. — S. lichenoides, Sow. Br. Fungi, t. 373. 

 f. 12. — 3. amphibola ; apotliecia larger clustered often irregular. 



Ach. Syn. 



On the trunks of old trees, near the ground. — Among the tubercles, 

 as they appear to Mr. Borrer, of this plant, Mr. Lyell and Mr. Robertson 

 find patellulce of a dull purplish-black, covered with an inseparable super- 

 ficial buff powder. The same patellulce occur on sandstone rocks in 

 Sussex, intermixed with what may possibly be abortive tubercles of the 

 Verrucaria. These are figured on the plate in E. Bot. t. 2642./. 2. c, 

 and look externally very much like the fructifications of a Lecanora. 

 But whilst Mr. Borrer knows of no other Lichen to which these patel- 

 lulce can be referred, he yet believes that they do not belong to our 

 Verrucaria. 



** Growing on rock or stone. Saxicola?. 



14. V. rupestris, Schrad. (immersed Bock Verrucaria); crust 

 indeterminate very thin whitish smooth, apotliecia small black 

 globose umbilicate sunk in a hollow of the crust and of the 

 stone. Schrad. Spicil. p. 109. t. 2./ 7. — V. Schraderi, Ach. 

 Syn. p. 93 — Lichen Schrad. — E. Bot. t. 1711. Schair. Lich. 

 Helv. p. 55.71. 103, 104. — Verrucaria immersa, Hoffm. PI. Lich. 

 t. 12./ 2—4 ? 



On chalk and calcareous stone, in which the apotliecia form cavities 

 often larger than themselves. — Mr. Borrer suggests that the V. immersa 

 of Hoffm. should be distinguished from this, and he observes that both 

 appear to have grown intermixed, as they frequently do on chalk, in the 

 specimen figured as Lichen Schraderi in E. Bot. But 1 am not aware of 

 the essential differences between them. 



15. V. conchma, Borr. (neat Bock Verrucaria); crust deter- 

 minate very thin tartareous continuous even grey somewhat 

 pruinose, apotliecia of a middle size prominent hemispherical 

 umbilicate black. Borr. in E. Bot. Suppl. t. 2623. / 1. 



Durham, Mr. Robson. Limestone rocks on the Durham shore of the 

 Tees, near Eglestone ; and on chalk on the Sussex Downs, Mr. Borrer. 

 Killarney, Sir T. Gage. — This differs from the V. rupestris by its limited 

 and even crust and its more prominent and larger tubercles. 



1 6. V. ekeina, Borr. (olive-green Rock Verrucaria) ; crust 

 thin tartareous cracked smooth slightly tumid above the tuber- 

 cles greenish-olive, apotliecia small immersed black between 

 h em i sphserical and conical at length emerging. Borr. in E. 



