186 ESSAYS. 



dromus," the terms convoluta and contorta are seemingly 

 employed synonymously, or nearly so (the latter most fre- 

 quently) ; at least I see no difference between the aestivation 

 of Allamanda, said to be contorted, and that of Vinca (rosea), 

 said to be convolute. Endlicher in this regard follows the 

 " Prodromus." In the new " Genera Plantarum " by Ben- 

 tham and Hooker this mode is most commonly designated as 

 contorta, sometimes as contorto-imbricata, rarely (Philadel- 

 phus, etc.) convoluta. I have myself, from a period as early 

 as 1840, employed the term convolute, thinking it unadvis- 

 able to have two names for the same thing, and wishing to 

 restrict, if it might be, the term contorted to cases of torsion. 

 Adrien de Jussieu, on the other hand, used convolute (with 

 strict Linnaean propriety) for regular imbrication with a high 

 degree of overlapping, thus giving two names to different de- 

 grees of the same thing. 



It being conceded, I presume, that the mode II should be 

 specifically distinguished, what name, on the whole, ought it 

 to bear ? If we follow prevalent usage, contorta will be the 

 term. But this term was unknown in this sense to the found- 

 ers of aestivation, Linnaeus and Brown ; it correctly expresses 

 the real state of things in only a few cases ; and where there 

 is torsion, it leads to a most awkward way of expressing it. 

 We have to write — " lobes of the corolla contorted and 

 twisted : corollae lobi contorti et torti," introducing dextror- 

 sum or sinistrorsum, 1 to express the direction of the overlap- 

 ping and of the torsion, which are not always the same. So 

 the most current name is the least appropriate. Convoluta 

 is as good a name as can be, and its use in the present sense 

 is not unconformable with the Linnaean use in vernation. 

 When well carried out, three or five or more petals, as the 

 case may be, are simply rolled up together. When the over- 

 lapping is slight, there is simply the tendency to convolution. 

 But if, as in other nomenclature, priority gives a paramount 



1 I note with satisfaction that Bentham and Hooker use these terms to 

 signify from left to right, or from right to left, of a person, supposed to 

 stand outside of the closed bud, which is surely the natural position of the 

 observer. 



