ESTIVATION AND ITS TERMINOLOGY. 185 



many cases, as in Asclepias for instance, the mode II passes 

 into mode III, the valvate, and may possibly have discerned 

 that under a phyllotaxic view these are more nearly related 

 than either is to mode I. I find, however, only one instance 

 in which he has indicated the distinction, namely, in the char- 

 acter of Burchellia, furnished to the " Botanical Register," 

 t. 435, 1820. Of its corolla it is said : " aestivatione mutuo 

 imbricata contorta." The phrase is interesting, as it seems 

 to recognize the distinction between the mode of overlapping 

 (which is that of our mode II) and the torsion, which only 

 now and then accompanies it. Looking over the " Plantae 

 Javanicae Rariores " to see if there is any later use, I find no 

 instance in which Brown has occasion to speak of this mode 

 II ; but it occurs in the portion of his associate, Mr. Bennett, 

 who (on p. 212) describes the petals of Sonerila as " aestiva- 

 tione convoluta." Had this term been thus employed by 

 Brown himself, and at an earlier date, I should regard the 

 terminology of these three modes of aestivation as settled, 

 namely : I, imbricata, II, convoluta, III, valvata. The first 

 and the third are established beyond question, although some- 

 what remains to be said about the first. 



But meanwhile another use has prevailed as respects the 

 second. In De Candolle's " Prodromus," the first general or 

 considerable work after Brown in which terms of aestivation 

 are employed, this mode is almost uniformly characterized 

 as contorta. I cannot at this moment trace the term to its 

 origin. It was probably suggested by the name Contortce, said 

 to have been given by Linnaeus to the Apocyneous natural 

 order ; and it seemed appropriate to the instances in which 

 the strong convolution of rounded petals, as in Oxalis, or 

 their lobes, as in Phlox, give an appearance like that of twist- 

 ing, although there is no twist or torsion. But it is to just 

 such cases, in which there is most of seeming twisting on 

 account of the strong convolution, that the term convolute is 

 now and then assigned in the " Prodromus" ; as in the char- 

 acter of Byttneriacece, and that of Malvaviscus. The latter 

 may perhaps be explained by the peculiarity that the petals 

 do not uncoil in anthesis. But in Apocynacece, in the " Pro- 



