Keegan : The Wych Ebu. ig 



less furrowed according" to agfe. The wood contains traces of 

 tannin and phlorog"lucin, no fat or resin, a moderate amount of 

 lignin, some g"lucose, and an enormouse production of starch 

 in summer, which, however, disappears in October from the 

 pith and becomes somewhat reduced in quantity in the rest of 

 the wood till Februar}-, when it reappears till flowering time, 

 then once more disappears during the bursting" of the buds, and 

 finally in July commences to be redeposited in full force ; the 

 wood of a branch of about one inch diameter, cut in May, had 

 about 2 per cent, of ash in dry, which yielded 15 per cent, 

 potash, 31 lime, 4.7 silica, 6.15 P-O^, etc. (Of our trees in the 

 division Apetalae the Elm contains the most potass in its wood.) 

 The bark retains its summer starch till towards the end of 

 November ; the bark of the branches contains about 2 per cent, 

 wax and a little resin, about 1.8 tannin with traces of phloro- 

 glucin, about 20 mucilage (occurring as cellulose-encased pro- 

 jections from the walls of roundish, large, strongly-refracting 

 cells or special sacs), and 10.8 ash, which in May has 12.4 

 soluble salts, 1 1.8 silica, 45.1 lime, 2.2 magnesia, 1.7 PoO^, with 

 traces of iron and manganese. The mucilage swells enormously 

 in water, contains unchanged cellulose, has an acidic function, 

 and arises apparently by the growing pressure provoking the 

 decomposition of the pectates of the middle lamellae of the thick 

 cell-walls of the parenchyma. 



Leaves. — The mesophyll is composed of one or two layers 

 of palisade cells occupying half its thickness and a regular 

 lacunar tissue of single cells extended horizontally and separated 

 from one another by wide intercellular gaps ; the cuticle is 

 normal ; the upper epidermis is of straight, polygonal cells, the 

 lower epidermis is of smaller and narrower cells with sinuous 

 walls, have simple and peltate hairs ; the stomata are small and 

 surrounded by accessory cells ; the petiole encloses three vascular 

 bundles at the base, which nearer the blade are fixed into a 

 closed ring which eventually opens in the form of the letter U. 

 At the end of July the leaves contain about 63 per cent, of water, 

 and the dried leaf yields about 2 per cent, wax, carotin, etc., 

 18 albumenoids, 2.9 tannin, and some free phloroglucin. much 

 glucose, a large quantity of pectosic mucilage (enclosed in round, 

 deep-reaching cells in the epidermises, petiole, and ner\es), 9.5 

 cellulose, and 9.8 ash which yielded 18.4 per cent, soluble salts, 

 19.17 silica, 33.8 lime, 5.2 magnesia, 3.6 P-O^, and 1.3 SO^. 

 The finely-tinted withered leaves of the autumnal forest yield 

 16.8 per cent, of ash in dry, containing 28-8 per cent, silica and 



1906 January i. 



