SCALE-LEAVES, FOLIAGE-LEAVES, FLORAL-LEAVES. 643 



The ovary contains structures which, from analogy with the eggs of animals, 

 have been tei'med ovules {ovula). They are also called " seed-buds ", as the seeds 

 are produced from them after fertilization. Formerly the name "germ-buds" was 

 frequently employed for these structures. Those botanists who endeavour to refer 

 the iutiuitelj' manifold members of plants to a few fundamental forms, and 

 especially to settle whether a certain structure is to be considered as a stem or a 

 leaf, have fought very much over the ovules. First of all, ovules were regarded 

 without exception as stem-structures, as parts, that is, of the axis, and the upper- 

 most portion of the stem which bears the ovules — or from which the supports of 

 the ovules branch off — were designated as fruit-axes. It was thought that 

 these fruit-axes divided up in the most varied manner, and that they sometimes 

 also became leaf-like, resembling flattened shoots, in which case the ovules would 

 arise from the margins of the flattened expansion. It was also supposed tluit 

 such fruit-axes might be united with the carpels, and the impression would then 

 be given that the ovules were produced from the carpels. Later, the ovules of 

 all plants were interpreted as leaf-structures, i.e. as parts of the carpels, and 

 their direct origin from the axis, that is, from the stem, was denied. Even those 

 ovules which ai'e situated on the apex of the axis, projecting into the centre of 

 the ovarian cavity, were regarded as outgrowths of tiie carpels, and it was sup- 

 posed that a freely-ascending, ovule-bearing column projecting into the cavity 

 of the ovary i-ose up from the base of the united carpels. Various other forced 

 explanations have been given, but it is hardly suitable to consider them here. 



Tiiese false interpretations are corrected when we no longer lay that stress 

 on the difference between stem and leaf, which was asserted by the advocates 

 of the two views quoted above, and when we remember that really all leaves 

 are produced from a stem, and that it is by no means easy to settle where the 

 stem ceases and the leaf begins. If we rigidly adhere to the histor\' of develop- 

 ment and to the actual fact rather than to those speculations on which is based 

 the conception of an "ideal plant", and if at the same time we set ourselves 

 against the attempt to refer all plans of construction to a single fundamental 

 ground-plan, we arrive at this result, that in many cases the ovules proceed 

 directly from the apex of the stem, and that even in the earliest stages of develop- 

 ment they have no organic connection with the carpels. They stand in the 

 same relation to the stem as carpels do, and there is no reason why they should 

 not, like them, be regarded as peculiarly metamorphosed leaves. They form 

 the last uppermost leaves originating from the axis, become subsequently a con- 

 stituent of the fruit, and may also be looked upon, in consequence, as upper 

 carpels. In such instances as these, two successive whorls of carpels are developed, 

 one situated below, whose members develop no ovules, and one placed above, 

 whose members are only formed of ovules and their supports. The lower carpels, 

 without themselves developing ovules, form the capsule arching over the upper 

 carpels which have been reduced to ovules. This view receives the more justi- 

 fication from the fact that similar conditions are observed in the stamens; that 



