22. Pinnated compound leaf of Ashtree-1, petiole or midrib-2, leaflets, jointed at 3 to petiole.

23. Radiate compound leaf of Clover.

terest, the long enumeration of varied forms will cease to weary; it will be forgotten as a theoretical study as it merges into the practical knowledge of the subject.

When the cutting of the leaf margin goes far into the substance of the leaf-Figs. 24, 84-so as almost to divide it into different portions, it becomes a partite leaf; but when the leaf is cut quite down to the midrib, forming as it were separate leaflets-Figs. 22, 88, 91, 98-we have the

24. Partite leaf of Burmarigold.

COMPOUND LEAF,

as distinguished from the simple leaves which have hitherto engaged our attention.

Compound leaves, although very varied in form, belong either to the same class as the leaves of the pea tribes-Fig. 19-or of the ash-Fig. 22-they are pinnated leaves; or they rank with the class which includes such as the horse-chestnut, the potentillas, &c., in which the leaflets radiate as it were from a centre. Pick up a fallen ash-leaf from the heap which strews the path after the first real frosty night of October, and you will have an excellent specimen of a compound leaf broken off at its joint with the main stem, and with its numerous little leaflets readily breaking off at their jointed attachments to the central petiole or midrib. The umbelbearing plants, such as the hemlock, offer us many specimens of extremely compound leaves. Fig. 25 is a specimen of the compound leaf of an umbelliferous plant; but is not, like some of the leaves of the family, doubly and trebly compound.

We must not bring our brief chapter to a conclusion without noticing certain leaves that are scarcely true leaves, and yet look extremely like them we mean the first, or seed, or cotyledonary leaves, with which many plants first make their appearance above-ground. These leaves do not resemble the true leaves of the plant, but, having served the purpose for which they were designed, of nourishing and protecting the first tender shoot, they wither and die. At Fig. 26, we see the seed leaves and first true leaves of the common white nettle, differing greatly from each other; in the March wild flowers will be found a different example of the same fact.

With the subject of leaves, we conclude the consideration of what are classed as the conservative or nutritive organs of plants. The root,

1

2

26. Seedling of common Dead Nettle-1, 1, the seed leaves or
cotyledonary leaves-2, 2, the proper leaves of the plant.

the stem, the leaves, are devoted to the preservation and development of the individual plant to which they belong; the whole plant itself tending to the development of the reproductive organs, by which the perpetuation and multiplication of the species is secured. Our next section is devoted to the consideration of these reproductive organs. We must not, however, part with our leaves, without noticing one of their most important fulfilments in the economy of nature, which is not sufficiently recognised. Leaves, it has been observed, throw off into the atmosphere a large amount of water; this water having been drawn up, by the roots of trees especially, from considerable depths. We can well imagine how great must be the amount of moisture furnished to the surrounding air by the leaves of an extensive forest, and we may understand how the unwise, indiscriminate clearing away of forests may tend to deprive a country or district of much of its natural humidity.

27. Curious leaf appendage of the Pitcher Plant.

THE reproductive organs of plants are composed of certain parts essential to the production of the seed. In themselves these essential parts are extremely simple, the gay colourings and beautiful forms of what is usually called a flower being by no means necessary to constitute a perfect blossom to the eye of the botanist.-But of this more hereafter.

one.

THE FLOWER-CUP, OR CALYX.

Our present lesson, like all other botanical lessons, must, to be worth anything, be a practical Let us take a few simple flowers, living ones if possible; but in case these should not be forthcoming with some of our readers, and at all seasons, we must give their portraits. Take the wallflower -Fig. 28-for one; the primrose-Fig. 29-for another; the loosestrife-Fig. 30-for the third;

D