58 



Keegan : The Holly. 



sclerenchyma ; the primary cortex of colienchyma and sclerous 

 cells is thin and remains green and living for a long- time ; an 

 external periderm of very stout cells is formed only in later 

 years — the whole finally becoming grey and inert, but no 

 secondary periderm, and therefore no rhytidome, are ever 

 produced. The wood contains ilicene, a little tannin and coni- 

 ferin, but no resin, phloroglucin, or glucose ; the starch nearly 

 disappears from the main stem in winter, but appears again in 

 March, then temporarily regresses at flowering time, and once 

 more slowly revives in summer to gradually diminish during 

 the autumn. A branch over i inch diameter, cut in September, 

 was chemically examined ; the dried bark contained 6*8 per 

 cent, of a highly remarkable gluey, viscid substance called 

 ilicic alcohol by Personne, but found to be a hydrocarbon called 

 ilicine C''''H'^° combined with a fatty acid, by Schneegans an 

 Bronnert (it constitutes the active portion of the well-known 

 bird-lime prepared from the Holly), also 2 '8 per cent, tannin, 

 a little resin, some pectosic mucilage, a considerable quantity of 

 soluble albumenoid, but no true fat, phlobaphene, or phloro- 

 glucin, and verv little or no sugar. Chippings from the stump of 

 a tree about 5 inches diameter, felled in the snow on 17th 

 February, yielded in the dried bark lo'i per cent, of ash which 

 had 12*5 per cent, soluble salts, 5'g silica, 44*7 lime, 6'2 

 magnesia, and 0*9 V^O" ; the wood yielded 0*5 per cent, of ash 

 w^hich had 48*4 soluble salts (sulphates), 27 silica, 1 1 '2 lime, 

 16 magnesia and manganese, 4*1 P'-O'' and 22*7 SO^. 



Leaves. — The 'wrinkled, keen, and glossy' leaves exhibit 

 structures of great beauty and eminent physiological interest. 

 There is only one vascular bundle in the petiole (a sign of 

 organic perfection, possibly consequent on pinnate disjunction, 

 according to Chatin). The blade consists of a strongly cuti- 

 cular epidermis, one layer of hypoderm cells, three compact 

 layers of short, close-set palisades densely chlorophyllous, and 

 a lacunar tissue forming a network of cells filled with starch, 

 and enclosing large irregular interspaces ; the prickly teeth and 

 thickened edges of the leaf are secured by layers of sclerous 

 fibres, and, save sonie short solid bristles on the petiole, there 

 are no hairs ; the stomata are of moderate size, and in number 

 amount to 276 per square mm. of surface. The leaf is nearly 

 o"5 mm. thick, and hence absorbs much heat and remains living 

 and active for about fourteen months. On 7th June the leaves 

 of last year's shoots contained i "6 per cent, of ilicene combined 

 Avith fatty acid (as in the bark), also some resin, but no fat oil 



Naturalist, 



