VERNATION, OR PR^EFOLIATION. 133 



in the Philosophia Botanica of Linnaeus. They were applied 

 onty to foliage, but they are equally applicable to floral parts. 

 Leaves, and all homologous or similar organs, if not simply 

 plane, will be either bent or folded or else more or less rolled up 

 in the bud. The first three of the following terms relate to the 

 former, the remaining terms to the latter. They are as to the 

 mode of packing 



Plicate or Plaited (Fig. 250) , when folded on the several ribs, 

 in the manner of a closed fan, as in Maple and Currant. This 

 occurs only in certain palmately veined or nerved leaves. 



Conduplicate (Fig. 249), when folded lengthwise, or doubled 

 up flat on the midrib, as in Magnolia ; a verj- common mode. 

 The upper face of the leaf is always within. 



Reclinate or Inflexed, when the upper part is bent on the 

 lower, or the blade on the petiole, as in the Tulip-tree (the blade 

 of which is also conduplicate) . 



Convolute (Fig. 251), when rolled up from one margin, i.e. 

 one margin within the coil, the other without, as in Apricot 

 and Cherry. 



Involute (Fig. 253) , both margins rolled toward the midrib 

 on the upper face, as the leaves of Water Lily, Violet, &c. ; 

 also the petals of Steironema and Tremandra. 



Revolute (Fig. 252), similarly rolled backwai'd from both 

 margins, as the leaves of Azalea and Rosemary. 



Gircinal or Circinate (Fig. 254) , when coiled from the apex 

 downward, as the leaves of Drosera and the fronds of all the 

 true Ferns. 



Corrugate or Crumpled, as the petals of a Poppy, applies 

 to the irregular crumpling of the otherwise plane corolla-leaves. 

 This is a consequence of rapid growth in length and breadth 

 in a confined space. 



251. The Ptyxis (or folding, &c.) of an individual leaf, of 

 which the foregoing modifications are the principal, should be 

 distinguished from the arrangement in the bud of the leaves of 

 a circle or spiral in respect to each other. The interest of the 

 latter centres in the flower-bud, i. e. in aestivation. To this the 

 following exposition is devoted, although sometimes applicable 

 to leaf-buds also. 1 



252. The disposition of parts in aestivation, in respect to 

 each other, is the result partly of their relative insertion, that is 



1 In the succeeding paragraphs, it becomes necessary to presuppose so 

 much knowledge of the flower as is implied in the free use of such terms as 

 calyx and corolla, sepals or calyx-leaves, and petals or corolla-leaves. See, 

 if need be, Chapter VI. Sect. I. 



