Linnaan Society. 479 



Mr. Hogg, F.L.S., exhibited specimens of Plumatella repens and 

 Spongilla fiuviatilis from a rivulet near Norton in the county of Dur- 

 ham. One of the Spongilla was attached to the larva-case of Phry- 

 ganea, and another to a tuft of liypnum riparium, which it had en- 

 tirely enveloped. 



June 19.— Mr. Forster, V.P., in the Chair. 

 Specimens of the tree which yields the Caoutchouc or India Rub- 

 ber of Commerce, and which proves to be a species of Hevea, nearly 

 related to the gulanensis of Aublet, were presented by Sir Everard 

 Home, Bart., Capt. R.N. 



Read a Description of a new species of Cattleya. By Mr. Robert 

 H. Schomburgk. Communicated by the Secretary. 



This splendid orchideous epiphyte, remarkable for the beauty and 

 fragrance of its flowers, occurs on trees, which skirt the banks of 

 Currasawaka and other streams which fall into the Rupununy, a 

 river of British Guiana. Mr. Schomburgk has named the species 

 superba, with the following characters : 



C. superba, sepalis lanceolatis acutis subsequalibus, petalis latioribus ob- 

 longo-lanceolatis undulatis denticulatis, labelli trilobi lobo medio sub- 

 rotundo-ovato dentato apiculato, pseudobulbis angustis, spatha magna 

 foliacea. 



Read likewise observations on some genera of Plants connected 

 with the Flora of Guiana. By George Bentham, Esq., F.L.S. 



The three genera which form the subject of this paper are Sym- 

 plocos, Seguieria, and Anthodiscus. To the first Mr. Bentham very 

 properly refers the Stemmatosiphon of Pohl, placed improperly by that 

 author in Meliacece. Mr. Bentham has satisfactorily shown that the 

 degrees of adhesion of the ovarium, and of the cohesion of the petals 

 in Styracinece afford only characters of secondary value, and that con- 

 sequently Sty rax and Halesia must form part of the same natural 

 family. Seguieria, which has been referred along with Petiveria to 

 PhytolacecE by Mr. Brown, is remarkable for its polyandrous flowers, 

 and its unilocular ovarium, with a solitary erect ovulum and a late- 

 ral stigma and the winged pericarpium. The following are the cha- 

 racters of the new species described by the author. Some of them 

 are so like Securidaca in appearance that they are frequently con- 

 founded in herbaria with that genus. 



1. S. parvifolia, stipulis minimis tuberculiformibus vix spinescentibus, 

 foliis ovali-oblongis basi in petiolum angustatis herbaceis. 



2. S. coriacea, stipulis longis validis rectis spinescentibus, foliis subsessi- 

 libus oblongis obtusissimis coriaceis. 



