12 Select Plants for Industrial Culture 



Acacia polybotrya, Bentham. 



New South Wales and Queensland. Attains a height of 40 feet 

 and yields, according to Mr. O'Shanesy, a good tan-bark. 



Acacia pycnantha, Bentham.* 



Victoria and South Australia. The " Golden Wattle " of the 

 colonists. This tree, which attains a maximum height of about 30 

 feet, is second only to A. mollissima in importance for its yield of 

 tanners' bark ; the quality of the latter is even sometimes superior to 

 that of the Black Wattle, but the yield is less, as the tree is smaller 

 and the bark thinner. It is a tree of rapid growth, content with 

 almost any soil, but is generally found in poor sandy ground, parti- 

 cularly near the sea-coast, where A. decurrens would not succeed, 

 and thus also important for binding rolling sand. It does not bear 

 severe frost. Experiments, instituted by me, have proved the abso- 

 lutely dried bark to contain up to 30 per cent, tanning principle, full- 

 grown sound trees supplying the best quality. The aqueous infusion 

 of the bark can be reduced by boiling to a dry extract, which in 

 medicinal and other respects is equal to the best Indian catechu, as 

 derived from Acacia Catechu and A. Surna ; it yields nearly 30 per 

 cent., about half of which or more is mimosa-tannic acid. This catechu 

 is also of great use for preserving against decay articles subject to 

 exposure in water, such as ropes, nets and fishing-lines. The fresh 

 leaves yield up to 6 per cent, and dry leaves up to 15 or 16 per 

 cent, of mimosa- tannin. Mr. G-oyder found the percentage of mimosa- 

 tannin in the stem-bark, estimated by LoewenthaFs method, to vary 

 from about 12 to 22 per cent. While, according to Mr. Siinmonds, 

 the import of the bark of oaks and hemlock-spruce into England 

 becomes every year less, and while the import of sumach and gambir 

 does not increase, the annual demand for tanning substances has 

 within the last twenty years been doubled. The import of tan-bark 

 from South-Australia into Britain during 1886 was 71,141 cwt., 

 valued at 51,632. A. pycnantha is also important for its copious 

 yield of gum, which is in some localities advantageously collected for 

 home-consumption and also for export. It is used in cotton-printing 

 and is of particularly good gluing quality. The wood, though not of 

 large dimensions, is well adapted for staves, handles of various imple- 

 ments and articles of turnery, especially bobbins [Dickinson]. It is 

 pale and can be easily worked. By improved methods, the fragrant 

 oil of the flowers could doubtless be fixed, though its absolute isolation 

 might be difficult and unremunerative. The tree as a rule seeds well. 

 An acre planted with this tree yielded five tons of bark in the seventh 

 year, worth 8 a ton here. 



Acacia retinodes, Schlechtendal. 



South-Eastern Australia. Ascertained so early as 1846 by Dr: 

 Hermann Behr to yield a good tanners' bark and much gum. This 

 Acacia is ever-flowering, and in this respect almost exceptional. In 



