90 LICHENES. [Verrucaria. 



what rugose, occasionally with a depressed opening on the summit, of 

 different sizes, the older falling off and removing a portion of the film 

 of the thallus with them. Acharius says, the minuteness of the apo- 

 thecia prevented his detecting the nature of the nucleus, but that all 

 appeared to him black within. However, the nucleus is pale, whitish, 

 semitransparent, greatly swelling by moisture, consisting of numerous 

 upright filaments with granular matter interposed ; the perithecium 

 passes under the nucleus. 



12. V. lencocephala, ACH. Thallus filmy, somewhat powdery 

 on the surface, very thin, grey, investing ; apothecia prominent, 

 subcylindrical, brownish-black, when young crowned with a 

 white powder consisting of gonyyli, when old naked. Adi. Lich. 

 Un. p. 286. Eng. Bot. Supp. t. 2642, /. 2. 



On bark of aged trees, near Killarney ; on moss in the shaded cre- 

 vice of a rock at Carig mountain, County of Kerry. What the cha- 

 racters of the Cyphelium of Acharius are, I am not aware, having no 

 opportunity of consulting the Stockholm Transactions for 1817 ; but 

 of the propriety of removing this species out of the genus Verrucaria, 

 I think, there can be little doubt. I can find no nucleus, but from the 

 aperture on their summits the apothecia discharge a cloud of simple 

 diaphanous cylindrical bodies whose length is about four times their 

 breadth ; their collection on and outside of the apothecia has a pale 

 flesh colour. 



13. V. rupestris, SCHRAD. Thallus whitish, continuous, thin, 

 arenaceo-scabrid, with a limit of a cream colour ; apothecia 

 numerous, small, immersed, aperture marginate, smooth, entire, 

 at length wide. Schrad. Spicilcg. p. 109, t. 2, f. 7, according 

 to Acharius in Lich. Un. p. 284. Eng. Bot. t. 1711, the figure not 

 good. 



On limestone at Dunkerron ; common. The thallus is whiter, 

 thicker, the apothecia are larger and less thickly set than in the suc- 

 ceeding. When the thallus is moistened it assumes a greenish tinge 

 which under the lens is seen to arise from a number of green points 

 thus made visible. The apothecia are rather loose in their respective 

 cells, and their black perithecium borrows a thin covering from the 

 thallus that closely invests it. 



14. V. immersa, HOFFM. Thallus greyish-white, continuous, 

 thin, pulverulento-scabrid, with a black limit ; apothecia nu- 

 merous, immersed, thickly set, minute, their aperture immar- 

 ginate, rough, cracked. Hoffm. PL Lich. t. 12, f. 2 4. 



On limestone, near Belfast, Mr. Templeton ; at Dunkerron com- 

 mon. In this, as in the preceding, the perithecium passes under the 

 nucleus. The apothecia are more minute, more rough, somewhat split 

 on their summits, and fit the cavities of the thallus less loosely. The 

 thallus is less rough, less white, and scarcely alters its hue by the ap- 

 plication of moisture. On meeting other lichens it throws up a black 

 border. 



15. V. concinna, BORR. Thallus determinate, very thin, 

 tartareous, continuous, even, grey, somewhat pruinose ; 

 apothecia of a middle size, prominent, hemispherical, umbi- 

 licate, black. Borr. in Eng. Bot. Supp. t. 2623, / 1 . 



