Illustrations of Indian Botany, Vol. 1/Rhamneae

by Robert Wight

LIII.—RHAMNEAE.

This like the last is a large order and like it distributed over every part of the world, except perhaps within the Polar circles being found throughout both the temperate, and the torrid zones. It consists for the most part of trees and shrubs, sometimes scandent, often erect, many of them armed with thorns or stipulary prickles. In most the leaves are alternate and in nearly all the flowers are small and inconspicuous, but with varied inflorescence, being axillary and fascicled, or subspicate, racemose or panicled. The fruit is equally variable being drupaceous and indehiscent with a very hard several-celled nut, or capsular and dehiscent, dividing into three valves. They however nearly all agree in having a 4 or 5-cleft calyx with valvate aestivation, small scale-like petals, and the stamens opposite the petals inserted under the edge of a flat disk which fills the whole cavity of the calyx, and covers the ovary : occasionally, as in Rhamnus, the flowers are unisexual, and one or two genera are said to have the ovary inferior.

"Calyx 4-5-cleft; aestivation valvate. Petals distinct, unguiculate, cucullate or convolute, or rarely flat, inserted into the throat of the calyx, sometimes wanting. Stamens definite, opposite the petals. Torus a flat or urceolate disk. Ovarium free or more or less immersed in the disk, or adhering to the tube of the calyx, 2-3-4-celled : ovules solitary, erect. Fruit free or more or less cohering with the calyx, fleshy and indehiscent, or dry and separating in three cocci. Seeds erect. Albumen fleshy, rarely none. Embryo about as long as the seed : radicle short, inferior : cotyledons large, flat.—Trees or shrubs, often thorny. Leaves simple, alternate (or rarely opposite), minutely stipulate."

Affinities. These are somewhat complex as they are considered rather nearly allied to several orders far removed from them according to the arrangement followed here such as Euphorbiacece, Byttnenacece, Rosacea?, &c, but those with which they seem most nearly to associate are the Celastrineae and Ilicineae, with which they were long confounded. From the former they were removed by Brown on account of their valvular, not imbricate, aestivation of the calyx; their stamens opposite, not alternate with, the petals : their indehiscent not capsular fruit, or when capsular septicidal not loculicidal dehiscence. From Ilicineae they are separated by the valvate aestivation of their calyx and by their discoid polypetalous, not monopetalous diskless, flowers. With Pomaceae they agree in the determinate number of cells of the ovary, in their ascending ovules, and alternate leaves. Generally speaking however they are easily distinguished from all these by their minute scale-like petals opposite the stamens, such certainly is the case with all those I have met with in India.

Geographical Distribution. Of the numerous species referred to this order some are found suited to almost every climate, the Arctic and Antarctic circles excepted. Rhamnus catharticus with some others being found extensively distributed through the more northerly countries of Europe, while Rhamnus hirsuta and Wightii are bolh found in the most southerly parts of India within a few degrees of the line—New Holland : North and South America : the Cape of Good Hope and Senegal in Africa : the Eastern Islands and China all claim indigenous species of this extensively distributed order, In India they abound, every jungle being profusely supplied with some species of Zizyphus, and of about 40 genera referred by Meisner to the order, 13 or about one-third of the whole are natives of India, showing how largely it partakes of the tropical character.

Properties and Uses. The well known Buckthorn, Rhamnus catharticus , belongs to this family, and the cathartic properties of its fruit are common to several other members of the genus. The fruit of Zizyphus on the other hand are destitute of cathartic qualities, and some of them are even wholesome and pleasant to eat among which the well known Bhir fruit, Zizyphus jujuba, may be mentioned. In China the peduncles of Hovenia dulces swell and become succulent, and are there much esteemed as a fruit resembling a ripe pear. Sageretia Theezans another Chinese plant, a member of this order is used there in place of tea by the poorer classes. Some other species are used medicinally in America, but upon the whole this order cannot boast the possession of any very important property, though, those it does enjoy, are of so mixed a character. The natives of this country use two or three species medicinally, but apparently place little reliance on them, as they seem to be employed rather as vehicles for the administration of more active ones, than for any useful quality they possess.

Remarks on Genera and Species. The genera of this order have been ably elucidated by Brogniart in his memoir on this family, published in the Annal. des Sciences Naturelles, who has on this head left almost nothing to be desired. In our Prodromus we have adopted his genera so far as the Peninsular flora extends, but that is not far, as we have only seven genera out of about 32 referred by him to the order. My recent collections have not added to the number, though one or two new species have been found, one, namely, of Berchemia and one of Colubrina. I have besides some variations of forms already described, but which I do not think can be elevated to the rank of species. The genera are conveniently divided into two sections, those namely, with dehiscent, and those with indehiscent fruit. To the former belongs Gouania, Colubrina and Scutia : to the latter Berchemia, Rhamnus, Zizyphus, and Ventilago—figures of all these except Gouania are now published in this work and in the Icones, and do not require further notice here.

EXPLANATION OF PLATE 73.

Scutia India—1. A branch bearing both flowers arid fruit—natural size.

2. The calyx, petals and stamens removed from the ovary.

3. Back and front views of the stamens, (he latter with the petal still attached.

4. The ovary detached from the flower.

5. ---cut vertically, ovules erect.

6. The ovary cut transversely, 2-celled, with a solitary ovule in each.

7. A fruit nearly full grown.

8. ---cut transversely, 2-seeded, seeds compressed.

9. A seed — natural size.

10. The same cut transversely, showing the embryo surrounded by albumen— with the exceptions mentioned, all more or less magnified.

EXPLANATION OF PLATE 74.

1. Colubrina Asiatica—natural size.

2. An expanded flower seen from above.

3. Stamens back and front views.

4. A full grown fruit cut transversely, 3-celled, with three triangular albuminous seed.

5. A seed—natural size.

6. The same—magnified.

7. Cut transversely, showing the foliaceous cotyledons enclosed in albumen.

8. The embryo detached—with the exceptions mentioned, all more or less magnified.

RHAMNEÆ

SCUTIA INDICA. (Brogn.)

RHAMNEÆ

COLUBRINA ASIATICA. (Brongn.)