266 M. WICHURA ON THE WINDING OF LEAVES. 



confined to ^ single metamorphosis, or that when the leaves of 

 several metamorphoses wind, the intervening metamorphoses 

 which do not wind, are separated from each other. In many 

 species of Dianthus, for instance, the stem-leaves, the petals 

 and the styles wind. Between these lie the metamorphoses of 

 sepals and stamens, which do not betray a trace of the wind- 

 ing movement. 



Winding and straight leaves are found united, even within 

 the single metamorphosis, when the form of the leaves belonging 

 to this metamorphosis is essentially altered from below upward, 

 or according to the position which they occupy on the axis. 

 Thus, for example, in Papyrus antiquorum, Willd., the lower, 

 rather broad stem-leaves do not wind, but the upper narrow 

 linear leaves preceding the inflorescence as bracts do. In many 

 irregular flowers likewise, only single leaves, mostly outwardly 

 conspicuous for prominent longitudinal growth, exhibit winding, 

 for example the iabellum of Himantoglossum hircinum, Rich. 

 Here belong, moreover, the so-called oblique flowers, e,g, ofHys- 

 sopus lophanthus, L., Pedicularis palustris, L., &c., the oblique 

 shapes of which arise from particular organs only of the flowers 

 curving, and thus destroying the symmetry of the whole. 

 Finally, the twisted awns of the Grasses must also be mentioned 

 here, since in all cases they occur only in one of the paleae 

 forming the floral envelopes. 



§8. 



The distinction in the shape of leaves belonging to relatively 

 like metamorphoses of different individuals, is fixed by the 

 systematic distinctions in the vegetable kingdom. The more 

 widely two species stand apart, systematically, the larger is the 

 sphere of possible differences in the development of the leaf, the 

 smaller therefore becomes the probability that they will behave 

 similarly in reference to the movement of winding. The divisions 

 into Cellular and Vascular Plants, Monocotyledons and Dicoty- 

 ledons, founded on the most general distinctions in the vegetable 

 kingdom, are consequently of no particular value for our purpose, 

 since each of these divisions includes formations of leaves of the 

 most varied kinds. It can only be said that the stem-leaves of 



