BUD AND LEAF. 



85 



178. Bud-Scales are transformed leaves, evidently provided against 

 accident or change of temperature. They usually fall when the leaves 

 unfold ; in the Currant and Southern Buckeye they revert to the leaf- 

 form and persist. 



179. Vernation (L. vernus, belonging to spring) is the 

 arrangement of leaves in the bud ; it is sometimes called 

 Prcefoliation. The leaf, in regard to itself and its axis, or 

 stem, is Open, Folded, Rolled. 





The Folded 



Fig. 109. — Vernation ; different modes. 



The Open Leaf is seen in the Mistletoe (Pig. 65) 

 Leaf (Pig. 109) is Conduplicate (A) when its 

 halves fold perpendicularly, as in the Mag- 

 nolia, Oak, Cherry ; Plicate (B) when folding 

 like a fan, as in the Currant ; Redinate (C") 

 when conduplicate and bending on the leaf- 

 stalk, as in the Tulip-tree. The Rolled 

 Leaf is Circinate (D), coiled downward 

 from the top, as in the Pern ; Convolute 

 (E), straight, one edge coiled round the 

 other, as in the Plum ; Involute (P, both 

 edges rolled inward, as in the Violet and 

 Lotus - Lily ; Revolute (Gr) , both edges 

 rolled outward, as in the Dock and Aza- 

 lea. 



180. Leaves, as regards one another in ver- 

 nation, are: Equitant (H) when conduplicate 

 leaves bestride each other, as in the Plags 

 and Sedges ; Half- equitant, or Obvolute 

 (I), conduplicate bestriding one margin only, 

 as in the Sage; Imbricate (L. imbrex, tile), 

 open, overlapping one another, like tiles 

 on a roof (J), as in the bud-scales of the 

 Horse - Chestnut ; Induplicate (K), partly 

 folded, touching, margins turning in; Val- 

 vate (L, M), convex, barely touching at the 

 neighboring margins. 



181. Leaf Arrangement (Phyllotaxy). — 

 Leaves, in position on the stem, are oppo- j,„^,„„^^^^, 

 SITE when opposed to each other (makmg 

 a pair) on the same circumferent line, as in the Honeysuckle (Pig. 



8 



Via. 110.— Woodruff {As 



