Linncean Society, 379 



5thly, That in some of the poor and ill-consolidated coals, particu- 

 larly in the upper zone, the traces of vegetable organization are so 

 distinct, that even the generic and specific characters of the plants 

 can be recognised in the coal itself. 



Lastly, That wherever the mountain limestone has been inter- 

 polated between the bottom coal grits and the old red sandstone, it 

 can invariably be traced to thin out and disappear within a very 

 small area ; and hence it is inferred, that as calcareous matter ap- 

 pears never to have been elaborated in these regions, except at wide 

 intervals and in minute quantities, mighty convulsions are not ne- 

 cessary to account for the absence of the mountain limestone through 

 such large carboniferous tracts. 



The coal-field of Oswestry is not included in the application of 

 these inferences; for, like the great coal basin of South Wales, it 

 has been deposited upon a thick girdle of carboniferous limestone. 



LINN^AN SOCIETY. 



March 3rd and 17th. — Read a paper by the Rev. Patrick Keith, 

 F.L.S., on the Classification of Vegetables, — or Taxonomy^ as the 

 writer proposes to call it. After noticing the limited and imperfect 

 use of artificial methods of classification, as pointed out by Linnaeus 

 himself, whose well-known maxim is ** Methodus naturalis ultimus 

 botanices finis est et erit," Mr. Keith insists on the superiority of aji 

 arrangement founded on general structure rather than numberof parts; 

 and gives his opinion that there is but one system which is natural, and 

 that that system is Jussieu's. After enumerating some of the principal 

 supporters of this system, he mentions our celebrated countryman 

 Brown as at the head of those by whom it has been elucidated and per- 

 fected ; — paying at the same time a deserved tribute to the merits of 

 Mr. Don. He then proceeds to comment upon writers who in his 

 judgement have innovated upon Jussieu's nomenclature and arrange- 

 ment ; and, after some observations on Professor Lindley's Nixus 

 Plantarum, and the circular arrangements, concludes with a tabular 

 sketch intended to adapt the system of Jussieu to the present state of 

 botanical knowledge, without innovating upon its principles. 



April 7th. — Read a communication by George Bentham, Esq., 

 F.L.S., entitled, " On the Eriogoneae, a tribe of the order Polygoneae." 



This group, which is exclusively American, is distinguished from 

 the rest of the order by the presence of an involucrum, and by the 

 entire absence of the sheathing stipules from the leaves. The Erio- 

 gonecE agree with Rheum and Oxyria in having a straight embryo 

 placed in the axis of the albumen. The group consists of three ge- 

 nera, namely, Eriogonumy distinguished by its many-flowered invo- 

 lucrum ; Chorizanthe, a genus proposed by Mr. Brown, and distin- 

 guished from the former by having a single-flowered involucrum ; and 

 lastly, Mucronea, characterized by its bidentate involucrum, composed 

 of two confluent bractes. Mr. Bentham describes twenty-four species 

 of Eriogonum, eleven of Chorizanthe^ mostly from Chile, and one of 

 Mucronea. The great accession of new species is chiefly the result 

 of the labours of the late Mr. Douglas in California, and of Mr. 

 Cuming in Chile. 



3 C 2 



