276 R. T. BAKER. 



Searching for literature in regard to the matter, I 

 found that Mr. A. W. Lushington had drawn attention to 

 the "concentric rings" of Avieennia officinalis, as to 

 whether they were annual or not, in the "Indian Forester" 

 for 1893, Vol. xix, p. 104, to which the Hon. Editor adds a 

 foot note to the effect that these "rings" are not annual, 

 and gives a picture of a section of Avieennia wood after 

 Nordlinger, not mentioned in Solereder — the originals of 

 which I am unable to trace. This was followed by a letter 

 in the same journal, Vol. xxiii, p. 413, by Mr. J. S. Gamble, 

 who, whilst giving a list of so-called mangroves, makes a 

 plea for some one to investigate the wood rings of A. 

 officinalis, and to ascertain how far, if at all, the curious 

 structure of the wood is caused by periodical phenomena, 

 such as tides, etc. 



Mr. A. W. Lushington, of Masulipatum, in the same 

 journal, Vol. xxiv, p. 56, writes in reference to Mr. Gamble's 

 letter (supra), and takes exception to that gentleman's 

 statement that " the rings of Avieennia are obviously in 

 ho way periodical, for they are not concentric, but run 

 into each other," and on account of those characteristics 

 periodicity cannot possibly exist. He then goes on to 

 attribute this break in the concentric rings to forest fires. 

 Further, he propounds the theory that, possibly, the 

 monthly difference of the tides might have something to 

 do with these rings, owing to the trees being more flushed 

 with water at one part of the month than at another. 

 He next records how he experimented with Avieennia, and 

 found twenty-five of these spurious rings after two (2) 

 trees had been cut twenty-five months, and in another 

 thirty-five rings after thirty-five months. 



The editor adds a foot-note to the effect that a section 

 may show a different layer of tissue, probably bark, between 

 each layer of wood. 



