Several families of this genus contain trees rich in tannin, but most important are the Myrobalans (often, but incorrectly, written Myrabolams or Myrabolans), the unripe fruit of various species of Indian Terminalia.
Fig. 57.—Myrobalan Tree (Terminalia Chebula).
T. Chebula ([Fig. 57]), a tree 40-50 feet high, and yielding good timber, is the source of all the ordinary varieties, which differ only in the district from which they are obtained, and the state of maturity of the fruit. The nuts contain from 30 to 40 per cent. of tannin. Of the various sorts, probably those known as Bombays are least unripe, while “lean greens” are the most so. The unripe fruit is the richest in tannin. “Bombays” have a smooth skin in coarse wrinkles, and when cut are porous and light coloured. “J’s” (Jubbalpores) and “V’s” (Vingorlas), have finer and shallower wrinkles, and are harder, solider and consequently darker looking, but do not give a darker liquor, while “lean greens” are greener, have less yellow colouring matter, and consequently more nearly approach in character to sumach, which the tannin in many respects resembles, though probably containing more ellagitannic acid in proportion to gallotannic acid than the latter.
The “nuts” should be bright in colour, not worm-eaten, nor “waxy” or soft. If kept in a damp place they rapidly absorb moisture, and fall into the “waxy” condition, in which they are very difficult to grind, sticking to and choking the cutters or beaters of the mill.
Neither the large hard stones nor their kernels contain tannin, but the latter have an oil which gives a peculiar odour to leather. The tannin exists in large and rather thickly-walled cells, and is not very easily extracted; the skin is wrinkled, but the uncrushed nuts swell up to their original plum-like form when placed in water for some time. The bark is almost as rich as the fruit, and the tree also yields galls.
T. Belerica yields Beleric or “Bedda nuts,” which are downy, rounder and larger than ordinary myrobalans, and contain about 12 per cent. of tannin, used as adulterant of ground myrobalans. A sample of solid extract made from the bark of T. Belerica contained 70 per cent. of tannin.
T. tomentosa has downy nuts, containing about 10 per cent. of tannin, bark stated by de Lof to contain 36 per cent. of tannin. A sample of solid extract contained 56 per cent. of tannin. The bark contains about 11 per cent.
There are several other Indian species.
T. Catappa, “Badamier bark” of Mauritius, contains 12 per cent. of tannin.