270 Excerpt a Botanica. 



their form is linear, slightly attenuated towards the base ; 

 their very delicate membrane is in due time ruptured, and 

 the sporidia escape as in many Lichenes and Hypoxyleae. 

 The sporidia, in number ordinarily eight, are of an elliptical 

 or oblong form, their length being j^ths, or nearly 300ths, 

 and their width a little more than 100th of a millimetre. 

 They generally contain a greenish cellular substance, and are 

 surrounded by a very marked transparent margin. Some- 

 times they are empty and pellucid, only marked with a longi- 

 tudinal plait. These facts, which are easily verified, have been 

 observed in a specimen of L. pygma>a gathered by myself on 

 the shores of Brittany. 



The organization of the nucleus of L. confinis differs in no 

 other respect than in the dimensions of the parts, which is 

 worthy of attention, as the plant is one half smaller. The fila- 

 ments, thecas and sporidia are similar in form as in L. pyg- 

 mcea. The sporidia alone have this remarkable peculiarity, 

 that, being one-third shorter than those of pygmaa, they still 

 are equal in width, which renders them nearly spherical. In 

 a young state, on a specimen collected by M. Durieu at Gijon, 

 on the coasts of Spain, they are slightly longer than broad, 

 entirely pellucid, pressed together and longitudinally plaited, 

 although always marked with a margin. In an older state 

 they are tui'gid, filled with an utricular mass, and nearly glo- 

 bose. This, which I presume is the adult state, is seen on a 

 specimen collected on the coast of Normandy by M. Lenor- 

 mand. 



Hence it is evident that Lichina (comprising the two spe- 

 cies pygmcea and confinis) must be removed from the Phycece 

 and arranged in the tribe Collanacea, near the genus Syn- 

 alyssa in the family Byssacece, or at all events among the Li- 

 chens, in case we do not admit Fries's intermediate family of 

 the Byssacece. 



As the genus Lichina contains only these two species there 

 will be little difficulty in distinguishing them, but the generic 

 characters must be modified as follows : — 



Apothecia terminalia, primo globosa, poroque simplici pertusa, de- 

 mum scutellato-urceolata, nucleum gelatinoso-filamentosum hya- 

 linum foventia. Asci erecti ampli, lineari-clavati, sporidia oblongo- 

 elliptica suboctona serie unica disposita continentes, paraphysibus 

 tenuissimis apice crispulo-incurvis stipati. 



Thallus cartilagineus, dichotomo-ramosus, teres vel plano-com- 

 pressus, olivaceo-nigrescens. 



