26 ANGIOCARPOUS LICHENS. 



Shaded rocks, Kerry, Ireland ! Br. Taylor ^ in herb. 

 Borrer, 



This does not accord with any species described in 

 Fee's Crypt. Exot. His monograph, in Ann. des Sc. 

 Nat. May, 1829, I have not seen. 



Genus 4. Pertusaria, D.C. 



Apothecium verrucaeform, normally covered by the cor- 

 tical layer of the thallus, enclosing one or many waxy, 

 gelatinous nuclei, enveloped by the thin, pale, membra- 

 naceous thallodal receptacle; ostiolum depressed, per- 

 forated; thallus crustaceo-membranaceous. 



In this genus a vertical section shows the white or 

 pale-coloured tartareous medullary layer (plate IX. 

 fig. 3 h), frequently with a narrow green layer, immedi- 

 ately under the pale waxy membranaceous cortical 

 layer (ci). The apothecia {A) are wartlike, very numerous, 

 and various in size, more or less confluent and deformed 

 from their crowded state, with depressions on their 

 summits, varying from a mere point to a disciform ex- 

 pansion, generally more or less coloured brown or black, 

 bearing on the surface the minute, prominent, perforated, 

 apices of the imbedded nuclei. Imbedded in the medul- 

 lary layer are the nuclei (c), either solitary or numerous, 

 surrounded with a pale, but very evident, tough, persis- 

 tent, membranous tunic or receptacle (d), white or slightly 

 coloured, gelatinous, consisting of large asci and numer- 

 ous very slender, fdiform, entangled, peculiarly floccose 

 paraphyses {e and C). The sporidia {B), which are very 

 variable in number and size, though of similar structure 

 in all the species, have a pale yellow, or light brown 

 central portion, enclosed in a double hyaline membrane 

 or tegument, giving, under the microscope, the appear- 

 ance of a very singular broad double margin. The 

 enclosed granules or ultimate spores are pale yellow, and 

 when disengaged have spontaneous motion. 



