G28 



REV. G. IIENSLOW ON VERNATION AND FOLTAOE 



Fig. 1. 



volute, and one of each pair slightly embraced the opposite leaf, 

 and so wrapped up the bud within it. 



(ii) pendulous. I have not met with any instance 

 of opposite leaves being pendulous in the young 

 state. 



(2) Alternate : (i) erect. — Good examples may 

 be seen in the Common and Portugal Laurels. As 

 the upper surfaces of different leaves cannot be in 

 contact, issuing from separate nodes and at differ- 

 ent elevations, each leaf is conduplicate, i. e. the 

 two halves of the blade are folded together and 

 thereby press their upper surfaces of the halves 

 against one another ; indeed so tightly is this done, 

 that it is not at all easy, in any instances, to sepa- 

 rate them. It may be noted here that the eondu- Fortu S a aure ' 

 plicate vernation is an extremely common one both for simple and 

 compound leaves, and the significance of it will be now very 

 apparent. It is sometimes further complicated by having the 

 surfaces plicate, as in the Vine, Beech, Maple, Currant, Basp- 

 berry, &c, conditions which are probably additional safeguards 

 against radiation. 



As other instances of the erect position may be mentioned 

 Rhododendron, the leaves of which, as of the Dock and Primrose, 

 are revolute ; but those of the Violet, Pear, and Michaelmas 

 Daisy are also erect but involute, while the Cherry has them 

 convolute. In all these the undeveloped leaf is cylindrical or an 

 elongated cone, erect, and offers no extent of surface, while the 

 margins, the most sensitive parts, are specially protected. 



(ii) pendulous. The Lime, Hazel, and Ampelopsis Veitchii are 

 good examples. In the case of the Lime, as soon as the bud ex- 

 pands and escapes from the winter (stipular) scales, the inner 

 stipules develop considerably : those on the upper side are con- 

 cave and ovoid and cover the upturned edyes of the conduplicate 

 leaves, which at once take a position in a vertical plane ; the 

 stipules at the sides elongate much more than the former, fur- 

 nishing some lateral protection to the whole bud, which now curves 

 strongly downwards, and somewhat resembles a mussel in shape 

 (fig. 2). As the bud continues to develop, the branch becomes 

 more and more strongly curved downwards, so that the leaves 

 are held vertically (figs. 3 and 4) ; and as the lower and older ones 

 increase in size, they assume a horizontal position and undertake 



