Naturalisation in Extra-Tropical Countries. 11 



Acacia polybotrya, Benthain. 



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

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



Acacia pycnantha, Benthain.* 



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,, 

 particularly 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 absolutely 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. Suma ; 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. Groyder 

 found the percentage of mimosa-tannin, in the stem-bark, estimated 

 by Loewenthal's method, to vary from about 12 to 22 per cent. 

 While, according to Mr. Simmonds, 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. The wood, though not of large dimensions, 

 is well adapted for staves, handles of various implements 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 the South of England it needs only wall-protection [Batemaii]^ 



