Rev. W. A. Leighton on the British Graphideac. 393 



as in Schserer's opinion (Spicil. 51), the sporidia in that plant 

 (Schser. Exs. 97 ! and 98 !) being of a subclavate form, 5-septate, 

 pale yellow. 



The plant named Spiloma fuliffinosum, Turn, and Borr. Lichen, 

 Brit. 37 {Spilama microclonium, E. Bot. 2150, not of Ach.), 

 which consists of small conglomerations of minute irregularly 

 rounded dark olive- gi-een globules, has, as I think, no connec- 

 tion with Lecanactis hjncea further than being parasitical upon 

 its thallus. 



Eschweiler (Syst. Lich. 14) describes the sporidia correctly, 

 " thecse fusiformi-cylindricae, annulatae,'' but figures them incor- 

 rectly in fig. 7. 



Plate VII. fig. 25. a. Vertical section of thallus and lirellae; b, sporidia. 

 [The engraver has made the sides of the sporidia angular, which is 



incorrect.] 



7. Platygramma. 



Apothecium lirellseform, subsimple or radiate; perithecium 

 none ; lamina proligera free ; disk plane, open, naked, without 

 any margin. Thallus crustaceous. 



Name from TrXarj)?, broad, and ypdfifia, a letter. 



1. Plati/fframina Hutchinsia, Jjeight. Thallus crustaceous, mi- 

 nutely cracked; lirellae immersed in elevated thallodal verrucae, 

 oblong or elongated, simple or branched, straight or flexuose ; 

 disk plane, ddated, naked; sporidia eight, in asci, fusiform, 

 5- or 7-septate, pale yellow. 

 Platygramma Hutchinsice, Leight. Lich. Brit. Exsic. 130 ! (1853). 



On shady rocks near the ground, Ireland ! Miss Hutchins in 

 herb. Borrer. Keswick, Cumberland ! in herb. Borrer. New- 

 ton Rocks, Cleveland, Yorkshire ! Mr. J. G. Baker. 



Thallus thin, crustaceous, spreading over the face of the rock 

 apparently to some extent, bordered by a raised tubercular black 

 serpentine Ime, especially visible in young plants, or smaller 

 portions of the plant, of a dull or dirty pale yellow on the ex- 

 terior, white within, continuous and smooth to the naked eve, 

 under a lens cracked into ver)' minute areolae, which are mi- 

 nutely verrucose. LirelUe very numerous, scattered without 

 order over the entire surface of the thallus, each imbedded in a 

 separate elevated thallodal wart, the smooth sides of which form 

 a narrow margin to it, of a paler yellow than the thallus, infi- 

 nitely variable in shape and size, round and minute, oblong, 

 linear, branched into two, three, or many and multiform ramifi- 

 cations, straight or curved, and wavy and flexuose, dark brown. 

 Disk on a level with the surface of the thallodal wart, concave 

 without any proper border. In section each side of the upper 

 portion of the nucleus is brown, dense, and thickened, but of the 



