Page:Illustrations of Indian Botany, Vol. 1.djvu/120

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48
ILLUSTRATIONS OF INDIAN BOTANY.

stance, which he calls Polygaline, under the form of brilliant pale coloured scales at first insipid, afterwards acrid and burning to the taste, insoluble in distilled water, and but sparingly soluble in alcohol. M. Dulong on the contrary, procured one, deliquescent and very soluble in water and alcohol. M. Peschier states that he obtained from 6 ounces of the root 100 grains of an alcaline substance, united with a new acid, which he has called acide Polygalinique. The Krameria or Ratany root remarkable for its astringent, properties and for its extensive employment by preparers of Port wine in Britian, is derived from another genus of this or a nearly allied family. The species of Xanthophyllum are trees that furnish timber of considerable size, and being besides handsome flowering plants, deserve a place in the garden, as does Polygala arillata a very handsome flowering shrub, not uncommon on the higher hills of this country. The properties of both Xanthophyllum and P. arillata if they possess any, are unknown. It seems to me desirable to remove the latter from the genus Poly gala, from most of the species of which it differs very widely in habit and in the arillus which covers the whole of the seed.

Remarks on Genera and Species. Three genera only, of this order, have as yet been found in the Indian Peninsula, viz. Polygala, Xanthophyllum, and Salomonia. The first of these, is a very old genus, has been long known as a native of India, but of which it appears Dr. Roxburgh knew only 'Z peninsular species, these have now been increased to 14 and Dr. Wallich and Mr. Royle mention several others, not met with in this part of India. Xanthophyllum is a genus originally established by Roxburgh for two Silhet trees, but is now found to extend nearly to the southern extremity of the peninsula, as I have several species from Courtallum, and one from Ceylon. It is also found in Java, whence Blume has 3 species to which he has given the name of Jackia, not knowing, that the genus had been previously named by Roxburgh. The genus Salomonia, originally established by Loureiro to receive a small Chinese plant, has recently had considerable additions made to it. Two have been found in Nepaul, three in Ceylon, and one in Malabar. The last, having been discovered for the first time in 1835, the genus has not yet found its way into our catalogue of peninsular plants, on which account I have availed myself of the present opportunity of making it known. The species of Polygala here represented, was selected on account of its being new to the peninsular flora, and under the supposition that it is a new species. On this last point however I have still some doubts, not but that my plant appears more distinct from P. perseearicefolia as figured by Wallich (Plant, rar. tab. 184) than many of the other allied species of the genus which are kept distinct, but because, I find they have a strong tendency to vary in their forms. I was particularly struck with this disposition while examining a very large series of specimens of P. Javana, presenting almost every form of vegetation and outline of foliage, but all agreeing in two points, the large wings of the calyx, and in having a curious 2 lobed membranous appendage, or arillus pendant from the carunculus. In like manner P. Heyneana has three, smaller, but in other respects similar, appendages hanging like flaps, nearly the whole length of the seed, from its carunculus, by which a number of sufficiently distinct looking specimens were with certainty associated. None of the other species possessed an equally certain guide by which to bring varying forms together, but from what I have observed in these two, I feel but little hesitation in concluding, that in some instances mere varieties are raised to the rank of species.

The genus Salomonia is distinguished from Polygalaby the absence of the large wing-like interior sepals; its 5 sepals being all nearly equal, by having four, not eight, stamens with the filaments united their whole length; and lastly, by the capsule being furnished on the margine with long tooth-like bristles, in place of being naked, or ciliated. Two species are introduced into the accompanying plate, one from Ceylon, recently discovered, and the other from Malabar.

The genus Xanthophyllum differs from the rest of the order in having symmetrical flowers, except the stamens, and exalbuminous seed. Here in place of three petals firmly united at the base into one, there are 5 petals, corresponding in number, and alternate with the lobes of the calyx, but the stamens retain the unsymmetrical character of the order. It differs further from the character of the order in having the placentae parietal in place of in the axis of the ovary. The species of Xanthophyllum here figured I at first doubted, whether to consider a narrow-leaved variety of one of Roxburgh's species, or distinct from both ; the latter I now think the more correct view ; partly on account of the difference of appearance of this plant, but much more