202 ILLUSTRATIONS OF INDIAN BOTANY- 



Identity of these two plants. This fact, it seems probable, will cause some confusion, since it now 

 ai>i>t!urs that Porana voluUUs^ the tjpe of the genus Parana^ is generically identical with 

 Breweria Rovhurghii^ and I presume with all the other species of that genus, but is not iden- 

 tical with all or perhaps any of the associated species of Porana. This is a point which it 

 ijeems necessary to examine carefully, and which, now that it is suggested, will, I trust, engage 

 the attention of some Botanist having adequate materials to enable him finally to dispose of 

 a question that may lead to the breaking up of several genera. Among the examples given in 

 the supplementary plate will be found, for more easy comparison, analyses of Porana voluhilis^ 

 Breweria Roxhurgkii^ and Porana racemosa. Of the latter, 2 sections of the ovary are given, 

 one transverse, exhibiting the normal form, 2-celled, each 1-ovuled; the other longitudinal, show- 

 ing one further advanced with a solitary erect ovule; the other having already aborted as the 

 mature fruit is one-seeded. 



*'CoNV0LVULACE.i:. 



Rivea^ Argyreia^ and Lettsomia. 



"M. Choiay, In his Memoir on Indian Convolvulaceae, in taking up Loureiro's genus Argy- 

 HEiA, has changed its character so essentially, that every one of Loureiro's genuine species 

 must now be excluded. I say genuine, because if Choisy is correct in referring Argyreia 

 festiva. Wall, to A. acuta, I.our., which I doubt, then that is not a true species of his genus, 

 which, as defined by himself, has a 4-celled ovary, while A. festiva has it 2-celled. 



/'Loureiro^s character of the fruit of Argyreia is 'bacca subrotunda exsucca ^-locularis ;' 

 Choisy 8 y var turn 2-loculaTe 4-spermum.' If the berries in Loureiro's plants have four cells, 



ovary to Argyreia, Clioisy has altogether suppressed the original genus, and set up a most 

 distinct one m its place, while at the same time he has added to the confusion by placing in his 

 new genus, numerous species with 4-eelled ovaries and fruit. In fact, nearly the whole genus, 

 as it now stands in De CandoIIe's Prodromus, will, I apprehend, be found not to come within 

 his generic character. 



"It is a curious fact, that Roxburgh fell into a similar error in regard to his genus Ze^^ 

 somia which according to his definition, has 2-ceIled ovaries, while nearly all his species have 

 them 4-ceUed. When both he and Loureiro wrote, the same importance was not attached to 

 tnat point of structure that M. Choisy has shown it deserved, and their error is easily traced 

 Zl^l f ^ generalization. Loureiro must have examined a species with a 4-celled fruit, and 

 took It for granted all the others bad the same structure. Roxburgh ( 



f9TpTL"^ character of his genus Lettsomia, seems to have had a «p«ci«« u..ure uxm v..v. 

 fwn . 1- H '^' ""^'T^^ *^^^ ^^^ *^^ ^^^^'^ species with baccate fruit had likewise only 

 Za nn l* til^ consequently associated under that character many species with 4.celled ovaries, 

 ^nd only two or three having hem 2-celled. M. Choisy, in the course of his examinations, 



species 



ith 



of the former he has con- 



fs I oureiroid RnvK ""'1: f *^ ^^^^'' ^? ^^"'^^ ^'^y^''^' ^ut falling into the same error 



b Jn kduopd 1 ? • ^^?' \^^' ^generalized where he should have disslcted, and has thereby 



numerous snecLs hnvfn.^^'*^''' 1""?'^^'' ''''''^^^ ^"^^"« ^l^^^^^^er, ♦ovarium 2-loculare? 

 numerous species having ovarium 4-locuIare. 



to the^cieno/'rnrnnnr ^"'.'^3*^'^ ^^.^^f « Wundeis, with the least amount of inconvenience 



merely sliSv iSX t''""/^ ^^ S' ^^'^' ^^°^^^' ^^i«^ ^^^ ^^ ^'^J ^e" "^^"^ ^^ 



merely shghtly altering the cha^^^^^^ l,^,- the other two as defined by their 



:?iT!'i:_/^i ^'^^"^P^^' Clhoisy gives to Rivea a capitate or lamelliform 2-lobed stigma 



and 4-celled ovary: I propose substituting the word linear 

 Convolvulaceous plants having indehiscent^ fruit, ZLZT 



for 



stigmas. 



or 



to 



Tulus 



the same 



to Lettsomia 



eitsomia torms the transition from Argyreia to Ipomcea, having 

 and the 2-celled ovaries of the other. 



