182 ESS A YS. 



prefoliation, 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 different 

 category, that in which the parts being united into a tube or 

 cup, this is bodily plaited into folds, or otherwise 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 aestivation above 

 indicated. 



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

 plaited aestivation, and of analogous conformations of the tube 

 or cup of a calyx or corolla, or of the disposition of each piece 

 individually (whether re volute, involute, reflexed, inflexed, 

 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 with : 



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 neigh- 

 bors on either side, without overlapping. 



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

 and are to be viewed as members of a whorl. In mode I, al- 

 though they may sometimes be members of a whorl, some 

 parts of which have 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 Papa- 

 veracece, and even the calyx of Craciferm, the upper or inner 

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

 phyllotaxy of alternate leaves. 



The type of the latter, and the common disposition when 

 the parts are five, is with two pieces exterior, the third ex- 

 terior by one edge and interior by the other, and two wholly 

 interior. This is simply a cycle in § phyllotaxy, the third 

 piece being necessarily within and covered at one margin by 

 the first, while it is exterior to and with its other margin 

 covers the fifth, this and the fourth being of course wholly in- 

 terior. So, likewise, when the parts are three, one exterior, 



