Illustrations of Indian Botany, Vol. 1/Tiliaceae

by Robert Wight

XXVI.—TILIACEAE.

This order which takes its name from Tilia, the Linden or Lime tree, a northern genus, is yet principally of tropical origin, several large genera being found in India, and many

more in equinoctial America. They, like the other members of the class Columniferae, are characterized by the valvate aestivation of their calyx, combined with a polypetalous inferior corolla, and inferior stamens, with 2-celled anthers : the leaves are alternate, stipulate, and more or less clothed with stellate pubescence.

In this order trees and shrubs are the predominating forms, but herbaceous plants are also met with, two out of five Indian genera referable to the order being such. The leaves are alternate, simple, petioled, feather-nerved, entire, crenated, toothed or serrated, with two, usually deciduous, stipules. The flowers are bisexual, regular, racemose, or corymbose, occasionally solitary and axillary.

The calyx is 3—5 sepaled, valvate in oestivation, deciduous; the torus often more or less stipitate : the petals inferior, alternate with the segments of the calyx, and equal to them in number, occasionally supported on a short claw, furnished with a gland or nectarial pit, and imbricated inoestivation, rarely wanting. The stamens are numerous, inferior, sometimes inserted on the apex of the torus, the filaments cohering at the base. The anthers are oval or roundish, 2-celled, opening interiorly by a longitudinal slit. The ovary is usually stipitate, several celled, that is, composed of several united carpels ; the styles are also united into one, but with as many free stigmas as there are carpels in the ovary. The fruit is either capsular or drupacious, several celled, with many or few seeds : the seeds are attached to the central angle, sometimes furnished with an arillus. The albumen is fleshy, the embryo erect, the cotyledons foliaceous, and the radicle inferior or rarely superior.

Affinities. The affinities of this order are the same as the preceding, agreeing with them in their valvate oestivation of the calyx, but distinguished by their free stamens, glandular disk, and appendages at the base of the petals ; the great difference however between the capsular and many seeded pericarps of Corchorus, and the drupacious ones of Grewia, and some others, seem to indicate a want of uniformity of character in an important organ, unfavourable to this being received as a well constituted order. With this order Kunth and Bartling unite Elaeocarpeae, a course which has not been followed by other writers, though they are very nearly related, differing principally in the latter, having its petals lacerated or fimbriated on the margins, and the anthers opening by pores.

Geographical Distribution. The species of this order are very widely distributed, extending from the cold and inclement regions of the north, through every degree of latitude, and modification of climate to the extreme south, but the majority are found within the tropics. India according to Wallich's list has 50 species, and several have since been added. Blume describes 21 from Java — and the authors of the Flora Senegambiae 15 from that portion of Africa. It is remarkable that though both genera and species are frequent in America, Humboldt seems only to have found 16, at least that is all that is characterized in his synopsis. The Indian Peninsula according to our list has 32 species, one of which Berria Ammonilla is admitted as doubtful, I have never met, with it on the continent, though it abounds in Ceylon. Among the Senegambiam species it is interesting to observe the numerous coincidences existing between them and the Indian forms : four out of 5 species of corchorus, enumerated as natives of that country, are identical with our Indian ones, and the fifth C. brachycarpus considered by the authors a new species, I suspect from the character and description to be the same as our C. fascicularis. They certainly agree in the peculiarities from which both names are taken, the fascicled flowers and short pods, while the other points of distinction seem too unimportant to admit of much value being attached to them, except that derived from the number of stamens, being 10 in the one, and about 5 in the other, the qualification about however, showing that they are not constantly 5 in the Indian form leads to the inference that they may be found equally liable to variation in the African, if many specimens were examined, and by so much reduces the value of a character, otherwise decisive of their dissimilarity. Should actual comparison of specimens prove them distinct, it must at the same time establish their very close affinity.

The genus Triumfetta has also its affinities in these very remote countries. T. trilocularis is common to both : T. pentandra scarcely differs in general appearance from some of our varieties of T. angulata, though it does in more important particulars, namely, in the number of its stamens, the cells of its ovary, and the form of its capsules. Triumfetta cordifolia has a con

TILIACEÆ

GREWIA MICROCOS (Linn.)

gener, though certainly distinct, in this country, in a yet undescribed species in my herbarium. Of 5 species of Grewia found there, one is certainly identical with our G. villosa, which being supposed new, by the authors, has received from them the very appropriate name of G. corylifolia. The other four species, I am unable to identify, from description only, with any of our species of that most difficult genus. Of the Javanese species several are common to this country, and one or two perhaps to Senegambia, showing, that although limited in their range by latitude, they have a very extensive range of longitude.

Properties and Uses. So much has been said under this head in the preceding orders of the class Columniferse, which all enjoy analogous properties, that but little is left to be said here. The Tiliaceae like the other members of that class are mucilaginous and emollient in their properties, and as such, are employed in medicine, in almost every country in which they are found, a few, such as Corchorus olitorius are used as pot herbs. But it is in the arts they are most extensively applied. The fibres of the bark of nearly all, are esteemed on account of their strength, and in this country are spun into cordage, or made into cloth. The fabric known in England under the name of Russian mat or bass, is made from the inner bark of the Lime tree, Tilia europaea. The wood of several kinds is also valuable : the excellent Trincomalee wood of Ceylon, is the produce of Berria Ammonilla. The Grewia elastica, of Royle, affords timber much valued for its strength and elasticity, and is therefore used for making bows and bandy shafts. A Brazilian species Lechea paniculata affords a bark used in tanning leather.

Remarks on Genera &c. The number of genera enumerated as belonging to this order in Lindley's natural system of Botany is 22 certain, and 7 doubtful. Of the first, 5 are found in India and Java, and of the last one Vatica, is Indian, and has already been referred, in our Prodromus, to Dipterocarpeae as identical with Roxburgh's Shorea. The Indian genera are for the most part easily distinguished, Corchorus with the exception of C. capsularis has elongated many seeded capsules : Triumfetta has them somewhat globose, covered with hooked bristles, and few seeds : Grewia has baccate or drupacious fruit : and Berria winged capsules. Brownlowia, a genus of Roxburgh, but most strangely omitted in his flora Indica, is distinguished by its tri coccous capsules.

The Indian species of these genera are with the exception of Grewia, generally of easy discrimination, but some of those of Grewia, if really distinct (which I somewhat doubt) are most difficult to distinguish with other than most perfect specimens, the fruit affording the best, if not indeed the only marks by which they can, with certainty, be determined. G. orientalis and G. columnaris, are so much alike, that I find it almost impossible to say to which I ought to refer many specimens, not in fruit, which have recently been added to my collection. Our G. emarginata is very nearly allied to both, but readily distinguished by its globosely lobed fruit. G. hirsuta and G. pilosa are also so closely allied that it becomes difficult to decide to which, some of the extreme forms of each belong, and leads to the inference that they are but varieties, unless the cleft petals of the latter be found sufficiently constant to keep them distinct Grewia villosa of India is certainly identical with G. corylifolia of the Flora Senegambiae, but I cannot perceive that any of the others are, unless perhaps G. bicolor, which from description, appears very nearly related to G. Kothii, except in the fruit which is stated to be globose in the one, and 2-lobed or dydimous in the other, apparently an excellent distinction. As this is a very difficult family, I propose shortly publishing figures in my Icones, of a number of them.

EXPLANATION OF PLATE 33.

1. Flowering branch of Grewia Microeos—natural size.

2. A flower, the sepals drawn back to show the petals and stamens.

3. The same, sepals and petals removed, showing the elevated torus, and the attachment of the stamens

round the ovary—the upper figure a detached petal, showing its glandular appendage at the base, surrounded by a fringe of short hairs.

4. Stamens back and front views.

5. Ovary cut vertically.

6. The same cut transversely.

7. Full grown fruit cut transversely—all more or less magnified.

8. A mature fruit—natural size.

EXPLANATION OF PLATE 34.

1. Flowering branch of Berria Ammonilla—natural size.

2. A flower closed showing the relative size of the sepals and petals, and that the former are partly united at the base.

3. The same forcibly expanded.

4. Ovary and sepals partially removed, showing the relative situation of all the parts of the flower.

5. An anther.

6. The ovary cut vertically, showing ovules pendulous in the cells.

7. The same cut transversely.

8. A full grown fruit.

9. The same cut transversely, showing by the presence of the full number of wings, that in this instance, one of the cells of the ovary has aborted in the course of its progress towards maturity.

10. One of the valves of the capsule removed, showing by the partition in the centre between the seeds, that the dehiscence is loculicidal.

11. A seed.

12. The same cut vertically.

TILIACEÆ

BERRYA AMMONILLA (Roxb.)