Illustrations of Indian Botany, Vol. 1/Hippocrateaceae

by Robert Wight

XXXIV.-HIPPOCRATEACEAE.

A small order of tropical arborescent or climbing shrubs, with opposite, simple, undivided, toothed, or entire, somewhat coriaceous leaves, and small deciduous stipules. The flowers are small, bisexual, regular, arranged in racemes, corymbs, or axillary fascicles.

The calyx consists of five, or very rarely four or six, small persistent imbricating sepals. The corolla is composed of five, equal, inferior petals, alternate with the sepals, slightly imbricated in aestivation. There are only three stamens, by some the filaments are described as distinct, by others they are said to be free above, but dilated and usually cohering at the base, forming a cup or disk-like covering to the ovary. Anthers terminal, one or 2-celled, in the former case opening transversely across the apex, in the latter longitudinally. Ovary superior, hid under the disk of the filaments, 3-celled, with several superposed ovules in each, either ranged in a single or double row, and attached to the axis : styles 3 cohering into 1 : stigmas 3 united, or distinct. Fruit either baccate with one or several seeds, or composed of three samaroid 2-valved carpels. Seeds exalbuminous, embryo straight, radicle pointing to the base, sometimes winged, cotyledons flat, elliptical, oblong, somewhat fleshy.

Affinities. These are uncertain, some Botanists considering this order more nearly allied to Acerineae and Malpighiaceae, while others at the head of whom is the celebrated Brown, and Dr. Lindley assert they are scarcely to be distinguished from Celastrineae; the latter Botanist even reduces this to a suborder of Celastrineae. Bartling places these two orders next each other, while Meisner on the other handretains this order in his class Malpighinae in the vicinity of Malpighiaceae, and Erythroxyleae. To me it appears that in a strictly natural distribution of the orders it should rank near Celaslrineae, if not, as Dr. Lindley has done, form a section of that order, but so long as the orders themselves, are distributed according to an artificial arrangement depending on the insertions of the petals and stamens, whether hypogynous or perigynous, I fear it must be retained in its present place. In itself, the order does not seem well constituted, as resting on a peculiarity of structure which I cannot help viewing as of secondary importance, the unsymmetrical (ternary) stamens and dilated cohering filaments, while the fruit, which generally affords more valuable characters, differs most widely in the different genera. The characters how- ever derived from the relative number of stamens and sepals, added to the very unusual development of the filaments are so very singular, as well to entitle them to a degree of importance not usually accorded to them, and even to raise them superior, in this particular instance, to those taken from the peculiarities of the fruit and structure of the seed, and, for the same reason that they unite Salacia with a baccate fruit and Hippocratea with three samaroid carpels, exclude Celastrineae, though in both orders "the insertion of the ovules is either towards the base, or is central, and the direction of the radicle is always inferior" as observed by Mr. Brown.

Geographical Distribution. This order is altogether of tropical origin, the larger portion appertaining to America. Some species of Hippocratea and Salacia are found in Africa, and several more of both in India. Hitherto, these two genera only, have been met with in India, but are very generally diffused over it, and so abundant, that species of one or other are to be found in almost every jungle.

Properties and Uses. I am not aware of any use to which any of the Indian species of this order has been applied. The fruit of one African species Salacia pyriformis is eatable, its flavour is said to be rich and sweet. The seeds of Hippocratea comosa, a West Indian plant, are oily and sweet.

Remarks on Genera and Species. The Indian flora as already remarked only furnishes species of two genera, Hippocratea and Salacia. They are easily distinguished when in fruit by the 2-valved capsular carpels of the one, and the pulpy baccate fruit of the other. In flower they are not quite so readily distinguished, but may be by the anthers which are 1-celled, bursting across the apex in the former, and 2-celled opening lengthwise in the latter, and generally still more easily by the inflorescence which is panicled in Hippocratea, while

in Salacia the flowers are for the most part congested in the axils of the leaves. Of this order Roxburgh seems only to have known five species, three of Hippocratea and two of Salacia, or Johnia as he, supposing them a distinct genus, called them. Under Wallich's hands the number has swollen to 19, but whether these will all prove distinct when thoroughly examined and compared may be doubtful, as some of them vary considerably according to circumstances.

It is not improbable that the species of Hippocratea here figured may be one of them, but as it was impossible for me to determine that from a name only, and as it evidently differs from all those described by Roxburgh, I could not hesitate about naming it. I have another species from Bombay, communicated by Mr. Graham under the name of H. obtusifolia. It does not however correspond with my specimens of that species nor indeed with any of the other Indian ones with which I am acquainted. From H. indica these three species are all known at a glance by their larger sized flowers; from each other they may be thus distinguished. H. obtusifolia, calyx fleshy, entire on the margin, petals triangular, tapering to a point. H. Grahamii, calyx membranous, fimbriated on the margin, petals obovate—spathulate. H. Arnottinna, calyx flashy, lobes obtuse, entire on the margin, petals suborbicular, unguiculate, reflexed. H. Richardiana of the Flora Senegambias, if really distinct, must be very closely allied to our H. obtusifolia, (I suspect they are the same species) the figure of H. paniculata of the same work, shows that it more nearly approaches my H. Grahamii, but is quite distinct.

The species of Salacia cannot, so far as I have yet been able to ascertain, be thus briefly and clearly distinguished by the flowers. The fruit seems to afford better distinguishing marks but is often wanting in preserved specimens. The inflorescence also gives several pretty good characters such as, whether the peduncles have one or several flowers, whether in the former case, there are few or many aggregated in the axil of the leaf, and whether they are longer or shorter than the petiol—according to these marks they may be thus distributed.

1.—Peduncles 1-flowered—(from an axillary tubercle).

A. Peduncles few—(1 or 2 to 6 or 8).

S. Brunoniana. S. Roxburghii. S. prinoides. S. macrophylla, Blume, one from Ceylon, S. reticulata, R. W. one and lastly, S. senegalensis distinct, from Malabar, though for the present united with the Ceylon one, D. C.

B. Peduncles very numerous.

Two species from Mergui of which I have specimens are referable to this subsection—both, so far as I know, undescribed S. verrucosa, R. W. and S. multiflora, R. W.

These two subsections are perhaps too artificial to prove of much value in practice, as it is evident that change of circumstances may cause a species to pass from the one into the other.

2.—Peduncles several flowered.

A. Peduncles 2-3 cleft, bearing few subsessile flowers on the apex.

S. pomifera. S. oblonga. S. Javanensis, Blume. S. oblongifolia, Blume. S. melitotarpa, Blume.

B. Peduncles forked, each division terminating in a simple many flowered umbel, flowers longish, pedicelled.

To this subsection one Mergui species S. floribunda, R. W. belongs.

The new species of both genera of this enumeration may be thus designated and defined.

HIPPOCRATEA.

H. Arnottiana, (R. W.) Shrubby, twining, glabrous, leaves ovate, oblong, acuminated, coriaceous, remotely crenato—serrated on the margin; panicles small, few flowered, axillary and terminal : petals from broadly ovate obtuse to subreniform, unguiculate, carpels linear, spathulate, broadly emarginate at the apex,

Hab.-Malabar.

The flowers of this species are perhaps, about the

largest of the genus, and the form of the petals at once distinguishes it from the other four Peninsular species.

H. Grahamii, (R. W.) Shrubby, twining, glabrous, leaves coriaceous entire, from broadly ovate to suborbicular, acuminated : panicles numerous, large, many flowered, congested towards the summits of the branches, petals linear spathulate, obtuse, carpels obovate, obtuse, slightly emarginate.

H. obtusifolia, Graham's MSS.

Hab.—Bombay.

I am indebted to Mr. J. Graham, of Bombay, for my specimens of this very distinct species, which is at once distinguished from H. obtusifolia, by its obtuse spathulate, not ovate acute petals, and more easily by its long peduncled, contracted many flowered, not diffusely spreading panicles.

SALACIA.

A. Peduncles one flowered, few.

S. reticulata, (R. W.) Shrubby, twining, leaves oval or somewhat obovate, attenuated at the base, ending in a short blunt acumen, coriaceous, serrulate, reticulated (when dry) with numerous prominent veins : peduncles shorter than the petiols : petals ovate, broad at the base, attenuated upwards, exunguiculate, fruit large globose warty?

Ceylon and Malabar? partly communicated by Colonel Walker.

The Malabar plant above alluded to may belong to this species, but is not in flower. The leaves are similar in form but less distinctly reticulated, which may perhaps be attributable to age, if identical, the fruit is as large as a small apple, rough and warty on the surface, and from it I have added, with a doubt, the character of the fruit. This species is very nearly allied to S. prinoides, but is certainly distinct if the fruit I have described belongs to it, should it prove otherwise, it is distinguished by the form of the petals, which in this are broad at the base, tapering to the point and without a claw, in that, from broad ovate very obtuse, to suborbicular and with a claw.

B. Peduncles one flowered, very numerous.

S. verrucosa, (R. W.) Shrubby, bark of the flower-bearing branches everywhere rough, with small warty excrescences : leaves coriaceous, entire, lanceolate, acute at the base, ending above in a short blunt acumen; peduncles 1-flowered, very numerous, arising from prominent axillary tubercles, shorter than the petiols : petals broad at the base, exunguiculate, oblong, obtuse: ovules two, superposed, in each cell: fruit?

Hab.—Mergui. Communicated by Wm. Griffith, Esq.

The bark of the flower-bearing branches in this species are quite rough from the numerous small warty excrescences, the leaves which are very firm and coriaceous are from 4 to 6 inches long, and barely 2 broad at the broadest part; and the flowers, the clusters of which are nearly opposite, are so numerous as to form complete verticels.

S. multiflora, (R. W.) Shrubby, glabrous, leaves broadly ovate, lanceolate, rounded at the base, slightly acuminated and obtuse at the apex, coriaceous, quite entire : peduncles numerous, from axillary tubercles, 1-flowered, longer than the petiols: calyx deeply 5-cleft : petals orbicular, ovules about 8 in each cell of the ovary in two collateral rows : fruit?

Hab.—Mergui. Communicated by Wm. Griffith, Esq.

The leaves of this very handsome species dry of a pale green in place of, as in most others of a dark brownish green: they are from 8 to 10 inches long by about 4 broad, quite entire, and in the dried plant, slightly revolute on the margin. It appears a very distinct species and remarkable for having a double row of ovules as in Hippocratea, with the cells of the anthers placed transversely across the apex of the filament and opening outwardly, hence, when the fruit is known it. may form the type of a new genus.

Peduncles forked, divisions umbellately, many flowered..

S. floribunda, (R.W.) Shrubby, scandent, glabrous: leaves elliptical, obtuse at both ends, sometimes ending in an abrupt blunt acumen, very slightly crenate on the margin: peduncles axillary, solitary, nearly as long as the petiols, once or twice forked at the apex, each division ending in a dense cluster of small longish pedicelled flowers : calyx entire, 5-toothed : petals small, orbicular, reflexed: ovules 2 in each cell, collateral fruit?

Mergui.—Communicated by Wm. Griffith, Esq.

The compound inflorescence of this species gives rise to a suspicion that it might be a Hippocratea, but thtf decidedly 2-celled anthers forbids me entertaining such an opinion, unless supported by the presence of fruit in which my specimens are deficient.

EXPLANATION OF PLATES 46 AND 47.

46—1. Hippocratea Arnottiana, R. W. natural size.

47—A. 2. An expanded flower of the same.

3. An anther, showing it 1 -celled.

4. The ovary cut transversely 3-celled, with two ovules in each cell.

5. A mature capsule burst, showing the contained seed.

6. A seed removed, showing the downward direction of the wing.

7. A seed cut transversely.

8. The seed removed and divided longitudinally, to show the inferior radicle and embryo — all more or less magnified.

47—B. I. Salacia oblonga — an expanded flower.

2. The same, the sepals forcibly opened and the petals, removed to show the superior ovary and the disk-like expansion of the filaments.

3. Stamens showing the anthers 2-celled;

4. A diagram of the flower.

5. The ovary cut transversely.

6. A full grown fruit, natural size.

7. The same cut transversely, natural size.

8. A seed, the adhering pulp removed.

9. The same cut transversely — with the exceptions-mentioned, all more or less magnified..

HIPPOCRATEACEÆ

HIPPOCRATEA ARNOTTIANA (R.W.)

HIPPOCRATEACEÆ

A. HIPPOCRATEA ARNOTTIANA. : B. SALACIA OBLONGA. (Wall.)