ZESTIVATION 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 phyllotaxie 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: “ estivatione 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 “ Plant 
Javanice 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 “ zstiva- 
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 exstivation 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 zstivation 
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 Contorte, said 
to have been given by Linnzus 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 Byttneriacew, and that of Malvaviscus. The latter 
may perhaps be explained by the peculiarity that the petals 
do not uncoil in anthesis. But in Apocynacee, in the “ Pro- 
