LINNEAN SOCIETY OS" LONDON. Ixix 



tion of its raphe and micropyle, considered with reference to their 

 constancy or variability in large groups of plants, verifying and 

 following up those which have been ah-eady published by one of our 

 most careful observers, Mr. Benjamin Clarke, — on the constancy in 

 genera or orders of those various forms of pollen, which have been 

 described in detail by Mohl, Schacht and others as prevalent in large 

 groups, but some of which Mr. Darwin has recently shown to be indi- 

 ■vidual differences in different flowers of the same species, — on the con- 

 formity of anatomical structure of the stem with other characters on 

 which large groups are formed, which has chiefly occupied the atten- 

 tion of French botanists, — and any similar researches would be valu- 

 able contributions to our publications, provided their authors do not, 

 by attaching an undue or, at any rate, premature importance to cha- 

 racters they have thus brought to light, proceed at once to generaKza- 

 tion, remodelling the whole system of classification, and throwing 

 everything into confusion by new names and new combinations which 

 can never be safely adopted without re-examining and testing in detail 

 that complication of characters upon which the old ones had been 

 gradually established. Tabular arrangements of classes, orders, and 

 minor groups, regularly defined by new characters, are tempting to 

 make, and may look well on a black board ; but if we have hitherto re- 

 fused a place in ovu' Transactions to those which have been offered to 

 us, and if I do not here allude in particular to any of those which we 

 are continually receiving, it is because we have seen no evidence of 

 their being more than theoretical speculations, untested by a study of 

 the innumerable exceptions which Nature offers to all our systems. 

 And on this head I cannot resist applying to our own Transactions 

 and Proceedings the words of Cuvier, prefixed to theNouvelles Annales 

 du Museum, in 1832 : — " L'experience leur a appris, que ce qui dans 

 des reeueils de ce genre conserve un interet durable, ce que les 

 savants consultent longtemps encore apres la publication, ce sont les 

 descriptions exactes et les bonnes figures d'especes nouveUes, les 

 caracteres nouveaux decouverts dans les especes anciennes et propres 

 a en rendre la distribution plus natureUe, ou la determination plus 

 precise, les faits nouveaux bien constates dans leur histoire, les details 



positifs et bien decrits de leur anatomic enfin tout ce qui, une 



fois consigne par ecrit, demeure corame une partie integrante de la 

 science. Chacun pent s'appercevoir, au contraire, que les pures con- 

 ceptions de I'esprit, les dissertations theoriques, les hypotheses 

 variables au gre de Timagination qui les cree, en se renversant I'un 

 1' autre d'annee en annee, quelqu' eclat qu'elles puissent jeter, quelque 

 bruit qu'elles puissent faire au moment ou elle paraissent, tombent 



