54 AESTIVATION AND ITS TEEMINOLOOY. 



elaborate the former subject as he diil the hitter, and the few terms 

 given to the modes he recognised are for the most part defined merely 

 by a reference to their use in vernation. iEstivation as a botanical 

 character is comparatively recent, and its terminology is not yet quite 

 satisfactorily settled. I propose to consider, 1, what the leading 

 modes are, and 2, how they arc to be designated. 



1 . In the first place, the modes of aestivation may be conveniently 

 divided into two classes, those in which the parts overlap, and those 

 in which they do not. 



Of overlapping aestivation, only two principal kinds need be 

 primarily distinguished, viz. : 1, where some pieces overlap and 

 others are overlapped, i.e., some have both margins exterior and 

 others both margins interior or covered ; 2, where each piece of a 

 circle is overlapped by its neighbour on one side whik; it overlaps its 

 neighbour on the other. There are mixtures and subordinate modifi- 

 cations of these two, but no third mode. 



In asstivation without overlapping, there is, first, the rare case in 

 which the parts of the whorl or cycle never come into contact in the 

 bud ; and secondly, that in which they impinge by tlioir edges only. 

 There is also the case in which both margins of each piece are rolled 

 or bent inward, and the rarer one in which they are turned outward ; 

 and the apex of each piece may comport itself in any of these ways. 

 But these dispositions are those of the pieces or leaves taken separately, 

 and the terms applied to them are the same as in vernation or pre- 

 foliation, are used in the same sense, and so are not at all peculiar to 

 aestivation or prefloration. The like may be said of a remaining mode, 

 which, belongs, however, to a diiferent category, that in which the 

 parts being united into a tube or cup, this is bodily plaited into folds, 

 or otherwiie disposed. In which case the margin of the tube or cup, 

 or such lobes as it may have, may exhibit any of the modes of aestiva- 

 tion above indicated. 



Without further notice, then, of this last, the plicate or plaiied 

 aestivation, and of analogous conformations of the tube or cup of a 

 calyx or corolla, or of the disposition of each piece individually 

 (whether revolute, invohde, rejiexed, injlcxcd, and the like) — about the 

 terminology of which there is no question — omitting, likewise, for the 

 latter reason, the case of open aestivation, there are left three types to 

 deal wdth : — 



I. "With some pieces of the set wholly exterior in the bud to 

 others. 



II. With each piece covered at one margin, and covering by the 

 other. 



III. With each piece squarely abutting against its neighbours on 

 either side, without overlapping. 



In modes II. and III. the pieces arc all on the same level and are 

 to be viewed as members of a whorl. In mode I., althougli they may 

 sometimes be members of a whorl, some parts of which haAc become 

 external to others in the course of growth, they may, and in many 

 cases must belong either to two or more successive whorls (as in the 

 corolla of Papaveracea, and even the calyx of Cruci/ercc, the upper or 

 inner of course covered by the lower or outer), or to the spiral 

 phyllotaxy of alternate leaves. 



