VERNATION. 151 



the base of flower-branches are called floral ; the latter, however, 

 are generally termed bracts. 



255. With respect to succession, those leaves which manifestly 

 exist in the embryo are called seminal ; the first or original pair 

 receiving the name of Cotyledons (113), and usually differing wide- 

 ly in appearance from the ordinary leaves which succeed them. 

 The earliest ordinary leaves, termed primordial, as well as the 

 cotyledons, usually perish soon after others are developed to sup- 

 ply their place. 



256. As pertaining to the arrangement of leaves, we should here 

 notice the modes in which they are disposed before expansion in 

 the bud ; namely, their 



257. Vernation or PfSCfoliation, The latter is the most character- 

 istic name, but the former, given by Linnseus (literally denoting 

 their spring state), is the more ancient and usual. Two things are 

 included under this head : 1st, the mode in which each leaf con- 

 sidered separately is disposed ; 2d, the arrangement of the several 

 leaves of the same bud in respect to each other. This last is evi- 

 dently connected with phyllotaxis, or their position and order of 

 succession on the stem. As to the first, leaves are for the most 

 part either bent or folded, or rolled up in vernation. Thus, the 

 upper half may be bent on the lower, so that the apex of the leaf 

 is brought down towards the base, as in the Tulip-tree, when the 

 leaves are inflexed or reclinate in vernation ; or the leaf may be 

 folded along its midrib or axis, so that the right half and the left 

 half are applied together, as in the Oak and the Magnolia, when 

 the leaves are conduplicate ; or each leaf may be folded up a cer- 

 tain number of times like a fan, as in the Maple, Currant, and Vine, 

 when they are said to be plicate or plaited. The leaf may be 

 rolled either parallel with its axis, or on its axis. In the latter case 

 it is spirally rolled up from the apex towards the base, like a cro- 

 sier, or circinnate, as in true Ferns (see the young leaves in Fig. 

 94), and among Phsenogamous plants in the Drosera or Sundew. 

 Of the former there are three ways ; viz. the whole leaf may be 

 laterally rolled up from one edge into a coil, with the other edge 

 exterior, when the leaves are said to be convolute, as in the Apri- 

 cot and Cherry ; or both edges may be equally rolled towards the 

 midrib ; either inwards, when they are involute, as in the Violet and 

 the Water Lily ; or else outwards, when they are revolute, as in 

 the Rosemary and Azalea. 



