Q. ilex, Evergreen Oak. Fr. Chêne vert, Chêne yeuse; Ger. Grüneiche, Steineiche; Span. and Ital. Encina. South Europe, Algeria. Said to be somewhat stronger in tannin than common oak, yielding 5-11 per cent. of a rather darker coloured tannin, but well adapted to sole-leather. Good bark is smooth outside, without fissures, short in fracture.
Q. Suber, Cork Oak. F. Chêne liège; Ital. Sughero, Suvero. ([Figs. 46], [47].) The outer bark is cork; the interior bark contains 12-15 per cent. of tannin which is redder than that of ordinary oak. Trees at first produce an irregular cork, sold as “virgin cork” for ferneries, etc. After this is stripped, later growths are more uniform, and fit for use; tanning bark is only obtained when the tree is cut down. Bark is rough but pale-coloured on both sides and about 1 cm. thick; interior like ordinary oak, but more strongly furrowed. Produced chiefly on Mediterranean coasts, and formerly largely used in Ireland.
Fig. 47.—Section of Cork Oak, showing cork, inner bark and wood.
Q. pseudosuber, African Oak. Fr. Chêne faux liège. Algeria. Not stronger than English oak, but with more colouring matter, hence strikes quickly through leather. Bark very thick.
Q. Mirbecki. Fr. Chêne Zeen. Algeria. Rapid growth. Bark contains 8 per cent. of tannin.
Q. Tozæ. Fr. Chêne tauzin. Pyrenees and S. France. Bark contains 14 per cent. of tannin.
Q. coccifera, Kermes Oak. Fr. Kermes, Garouille ([Fig. 48]). South Europe and Algeria. Root bark is called “rusque” or “garouille”; averages 10-18 per cent. tannin, but trunk bark does not exceed 11 per cent. This tree is the food of the kermes insect, used for dyeing scarlet before the introduction of cochineal. Garouille is principally used in the south of France, giving a firm sole-leather of a disagreeable odour and dark brown colour.
Fig. 48.—Kermes Oak (Quercus coccifera).