140 
Forest Flora of Portuguese East Africa. 
Infisc, and natives who had worked in the trade could see no difference when I pointed it out to them, being inclined to think the difference in the flowers either the flowers of 
or the result of, horanlhus parasitism. There have thus been at least five species yielding bark which has been shipped, without any accurate knowledge as to their relative value! 
The same thing is happening in other parts of the world where other species are also included, and it is consequently not surprising to find the following remarks by Dr. J. Gordon 
Parker in the “Year Book of the Manchester, Liverpool and District Tanner’s Federation,” 1905, evidently under the impression that one species supplies all. “Mangrove Bark 
Probably no material differs so much in strength and character as the bark of the Mangrove tree, and no material is more deceptive in appearance; in fact, from a general 
examination of the bark no conclusions whatever as to its tanning quality or strength can be drawn. Some years ago Professor Eitner, of the Vienna Research Station, stated in 
a report that Mangrove bark would not make a satisfactory leather ; that it simply coloured the fibres of the pelt, and the resulting product dried out hard and horny and of a 
deep mahogany colour, and that it could not be claimed to be a tanning material worthy of any consideration. Dr. Ptessler, of the Freiberg Research Station, on the other hand 
reported in high terms of the value of Mangrove bark as a tanning agent, and either alone or blended with other tanning materials claimed that it produced leather of good 
quality, well-tanned, and of good colour. There is an old saying that experts always differ, but in the case of Mangrove bark these diametrically opposite views were probably 
both correct, i.e., each view correct with regard to the special sample or samples of Mangrove being experimented with. I possess a collection of over 50 different samples of 
Mangrove bark, and think I may safely say that there are 20 different and distinct kinds of bark among them. Probably as years go on, the number of different kinds of 
Mangrove brought to the market will increase, but of these 20 they all differ in character, colour, and tannin strength, yet all have a similar external appearance. Some samples 
show on analysis over 50 per cent, of tannin; many less than 20 per cent., some even as low as 2 per cent, and 3 per cent. Some samples contain a high percentage of soluble 
matter, which, although probably akin to tannin, does not combine with the pelt fibres at all readily, and although it is possible with such a sample to obtain a liquor of 60 or 8o° 
Bk., it will scarcely tan pelt, but imparts a dark mahogany colour, colouring the fibres through and giving the pelt the appearance of being tanned.” 
1 Ih-sc are the tanners difficulties, and if the Mangrove export business is ever to be of value here again they require attention. An interesting resumk of the subject 
appears in the Bulletin of the Imperial Institute, 1906, Vol. III., No. 4, from which the following specially interests us “ It has long been known that all parts of the 
the le In-l'i!^ 111 y l lClr barkS * C ° ntam tanmn ’ but U ' S ° nly com P arativel y recently that Mangrove bark has been systematically collected and imported into Europe for 
r a , „ “ Mangroves best known as yielding barks suitable for tanning purposes are Rhizophora mucronata, Rhizophora Mangle, 1 Bruguiera gymnorrhiza, Ceriops 
CandoHeana and Roxburghiana and kandel.a Rheedn.' Mangroves yielding barks rich in tannin are fairly widely distributed in tropical countries, and in recent years a good 
deal of attention has been paid to the exploitation of these materials in various countries, notably Germany and Belgium. The best known Mangrove barks in European 
commerce are probably those of German Last Africa, which have been made the subject of special study by Dr. Busse (Chem. Centr., 1899, 1 (4), p. 315), and by Prof. Kbrner 
tt^k"ak? e di , * e GtrbSChul '\ Fre,ber e> i8 99, *900. These results show that the richest Mangrove barks obtainable from German East Africa are 
rL - m from . Fh,zo P* lora mucronata, which may contain as much as 48-0 per cent, of tannin, though samples containing only 213 per cent were examined 
CanaoHn^ 1 1}l u S UIera gymnorrhiza, contained from 44 to 53 per cent, of tannin, whilst the ‘ Mkandaa’ and ‘ Mkamavi ’ bvks, obtained from Ceriops 
^ hT T-hS f PeCt,Ve,y ’ rontamcd 42 ’-3 and 40 5 P er ^nt. of tannin. Quite recently a similar series of barks from Zanzibar was examined at the 
Impel lal Institute, and the results, which were given fully in the Bulletin oj the Imperial Institute, 1904, Vol. II., page 165 showed that the Msinzi bark of 7 ™ t • a 
Ei? c J” " r ■»*, r™.« 3^8 and >3-8 per cent, of fair resp.Ll, ^0^ “an bl " 
Africa nr , ! T , ' , f , ^ f ° U ° W l ° sh ° W that these same s P ecies sh ° w lower percentages there, sometimes much lower. Queensland and West 
r d ’ b 111 lbe attC T “ the nat,ves make 100 much of Palm oil 10 bother with hark. “ In German and Portuguese East Africa where Mangrove bark 
discovered ^ TT / T f ^elsewhere, the Mangroves were at first cut down for limber, and the bark was wasted until its value as a tanning agent was 
3 - ws= 
-=rr •rws=s£=; “ .ts- :: 
Not belonging to tins Province. » This occurs with only a very few kinds of trees, and it would be strange if all these Mangroves did so.-T.R.S. 
