160 LICHENES. [Pertumria. 



7. Pertusaria. Ach. Pertusaria. 



Thallus cartilagineo-membranaceous, spreading, adnate, uni- 

 form. Apothecia verruciform, formed of the thallus, one-or 

 many-celled, each cell containing a nucleus, opening by a de- 

 pressed pore. — Named from pertusus, full of holes; in allusion 

 to the pores or depressed points in the wart, like excrescences 

 of the thallus. 



1. P. communis, DC. {common Pertusaria); crust greyish- 

 white smooth, warts of the apothecia crowded subglobose with 

 many depressed points. De Cand. Fl. Fr. ed. 1. p. 330. — 

 Forma pertusa, Ach. Syn. p. 109. — Lichen pertusus, Linn. — 

 E. Bot. t. 677.—Schcer. Lich. Helv. p. 64. n. 118. 



On trunks of trees, abundant. 



2. P. ceuthocdrpa, {cream-coloured Pertusaria); crust calca- 

 reous continued cream-coloured tessellated unequal smooth, 

 warts of the apothecia tumid globose smooth with black de- 

 pressed points. — Lichen ceuthocarpus, E. Bot. t. 2372. 



On slate rocks in Ireland, where it grows in large uninterrupted 

 patches, Miss Hut chim and Sir T. Gage.— This has a cracked or tessel- 

 lated crusty fewer, more globose warts, and larger dots than P. communis. 



3. P. fallax, Ach. (doubtful Pertusaria); crust somewhat 

 spreading plicato-rugose grey, warts of the apothecia crowded 

 irregular depressed above bordered by the swollen almost 

 gibbous and wavy circumference, pores solitary or many large 

 somewhat confluent distorted black. Porina fallax, Ach. Syn, 

 p. 110. — Verrucaria fallax, " Pers." — Pertusaria Widfenii, De 



Cand. Thelotrema hymeneum, Ach. Meth. — Lichen hymenius, Ach. 

 Prodr.—E. Bot. t. 1731. 



Not ^infrequent on the bark of old Oaks and other trees.— Sir James 

 E. Smith compares the warts of this species, cut perpendicularly, to the 

 grinders of some quadruped. There is, indeed, a peculiarly deformed 

 and distorted appearance about this plant ; and it is, along with two 

 other Pertusaria, four Variolarics, and two Isidia, (as forms of one and 

 the same species,) made synonyms to P. communis, by Sprengel, on the 

 authority of Meyer. — Mr. Borrer considers the present plant to rank 

 with the Thelotremata, as is evident from his remarks at the end of the 

 description of his T. Hutchinsice, E. Bot. Sujipl. t. 2652. 



4. P. isidioides, (Isidium-like Pertusaria); "crust thick 

 tartareous frustuloso-areolate yellowish-brown, tubercles small 

 globose pale immersed in tumid roundish warts except the 

 darker slightly prominent apex." — Verrucaria isidioides, Borr. 

 in E. Bot. Suppl. t. 2622. f. 1. 



Rocks, GlangarhT, near Bantry, Miss Hutchins.— " Acharius would, 

 perhaps, have placed this singular Lichen in his genus Porina : yet the 

 manner in which their apex usually emerges appears to point out a 

 closer affinity to the other Verrucaria. It is, in fact, one of the many- 

 links which connect the Pyrenula: of Acharius with his Endocarpa." 



5. P. crdssa, (thick Pertusaria); crust cartilaginous undu- 



