VERNATION OR PR^FOLIATION. 



Ill 



in Ferns (fig. 222 g), and called cirmiate (circino, I turn round) ; or 

 folded laterally, conduplicate, as in Oak (fig. 222 b) ; or it has several 

 folds like a fan, plicate or plaited, as in Vine and Sycamore (figs. 221 /,, 

 222 c), and in leaves witli radiating' vernation, where the ribs mark 

 the foldings ; or it is rolled upon itself, convolute or supervolute, as in 

 Banana and Apricot (fig. 222 d) ; or its edges are rolled inwards, 

 involute, as in Violet (fig. 222 e) ; or outwards, revolute, as in Eose- 

 maiy (fig. 222 /). The difi'erent divisions of a cut leaf may be 

 folded or rolled up separately, as in Ferns, while the entire leaf may 

 have either the same or a different kind of vernation. 



Other kinds of vernation receive their names from the arrange- 

 ment of the leaves in the bud, taken as a whole. Leaves in the bud 



Pig. 222. 



are opposite, alternate, or verticillate ; and thus different kinds of 

 vernation are produced. Sometimes they are nearly in a circle at the 

 same level, remaining flat, or only slightly convex externally, and 

 placed so as to touch each other by their edges, thus giving rise to 

 valvule vernation (fig. 222, h). At other times they are at different 

 levels, and are applied over each other, so as to be imbricated, as in 

 Lilac, and in the outer scales of Sycamore (figs. 220, 221) ; and 

 occasionally the margin of one leaf overlaps that of another, while it, 

 in its turn, is overlapped by a third, so as to be twisted, spiral, or con- 

 tortive (fig. 222 i). When leaves are applied to each other, face to 

 face, without being folded or rolled together,.they are appressed. When 

 the leaves are more completely folded they either touch at their 



Fig. 222. Diagrams to show the different Icinds of vematiou. o-gr, The folding of indi- 

 vidual leaves ; a and g being vertical sections, bode and /being horizontal, a, Beclinate 

 or replicate, b, Conduplicate. c, Plicate, d, Convolute, a, Involute. /, Revolute. a 

 Circinate. h-n, Folding of leaves when united together in the leaf-bud. The sections are 

 horizontal or transverse, and show the relative position of the leaves, and the mode in which 

 each of them is folded. A, Valvate, i, Twisted, spiral, or contortive. k. Opposite or 

 accumbent, with the margins reduplicate. I, Induplicate. m, Bquitant. n, Obvolute or 

 half-equitant. In all the figures the thickened portion indicates the midrib of the leaf and 

 the dot marks the position of the axis. 



