R. pentaphylla, “Tezera,” Algeria, is used by the Arabs for tanning goat-skins.
R. Thunbergii, Kliphout, Cape of Good Hope. A sample of the bark analysed in the Author’s laboratory contained 28 per cent. of tanning matter. A valuable tanning material, of reddish colour. The tannin is of the catechol class.
Several other species of Rhus are used in tanning. R. semialata yields Chinese and Japanese galls, containing up to 70 per cent. gallotannic acid. They are caused, not by a fly, but by the attack of an aphis, as are those of the allied Pistacia.[145] The aphides pass their asexual stage inside the gall, which is large and thin-walled. A similar aphis-gall is found on the American sumach. A specimen of the leaves examined at the Yorkshire College yielded only 5 per cent. of tannin.
[145] See Flückiger and Hanbury, ‘Pharmacographia.’
Mangifera indica, Mango, widely distributed in the Tropics. Bark and leaves rich in tannin, which gives green-blacks with iron.
CORIARIACEÆ.
Coriaria myrtifolia, French sumach (of which there are four kinds—fauvis, douzère, redoul or redon, and pudis). A poisonous shrub of South of France; leaves used for tanning, and as a sumach adulterant under the name of “stinco”; contain about 15 per cent. tannin. (Cp. [p. 272].)
Coriaria ruscifolia bark, the tutu of New Zealand, contains 16-17 per cent. of tannin.
Other Coriarias merit examination, and are known to contain much tannin.