146 



Keegan : The Hawthorn. 



10 per cent, (with 6 silica, 40-4 lime, and 37 P'-^O'). This com- 

 position clearly indicates an early decay of the vital powers, 

 and an excessive oxidation of the carbohydrates owing- to the 

 extraordinary stimulation of the respiratory processes concerned 

 in the evolution of the flower and the maturation of the lavishly 

 abundant fruit. 



Flower and Fruit. — The inflorescence is disposed in the 

 form of a corymbiferous cyme. The upper surface of the petal 

 is studded with papillae, and it is in these that the droplets of 

 odoriferous oil are mainly localised, whereas the tannoid matters 

 (rutin) preferably accumulate in the lower surface. The solar 

 radiation of early May is not sufficiently strong- to destroy the 

 odoriferous products of deassimilation, but at the same time it 

 is powerful enoug-h to favour their elaboration. The odour 

 belongs to the class 'aminoid,' but it is tempered somewhat 

 and rendered redolent of ammonia by the decomposition of 

 lecithin present in the flower and its stalk. In the red varieties 

 of the flower tannin takes the place of rutin, and the essential 



011 is consumed. The cyme fully developed yields 5*8 per cent, 

 of ash having 38 percent, soluble salts, 21*5 lime, 4-1 magnesia, 

 8*9 P^O' and 3*8 SO'^ The fruit has been variously regarded as 

 an achene, a pome (i.e., the mesocarp belongs to calyx and 

 receptacle, and not to ovary), and finally a drupe. It matures 

 about 15th September, and then consists of (i) an epicarp of 

 tabular cells and a non-distinct hypoderm, (2) a flesh (mesocarp) 

 of spheroidal and ellipsoidal cells, and (3) a nucleus (endocarp) 

 made up of a layer of flattened sclerous cells, a layer of small 

 ditto with enclosed crystals, and a layer of fibres. The seed- 

 covering is thin and non-sclerified, the endosperm is relatively 

 voluminous, and the cotyledons thick ; both the latter contain 

 aleurone and oil as reserve materials, but no starch. The 

 pericarp contains an iron-blueing tannin, an ill-developed red 

 pigment, much starch (none in Cherry, Plum, etc.), mucilage, 

 and various sug-ars. The fruit (air-dried) yields about 2 percent, 

 of ash having 33 per cent, soluble salts, 19-4 lime, 5 magnesia, 

 io'5 P^O'^ and 2*4 SO''. It would seem that the extreme stony 

 hardness of the endocarp here is brought about at the expense 

 of the starch and of the tannin, which latter in consequence is 

 never fully converted into pigment. 



Summary. — The extreme fineness of the wood-vessels, as 

 well as the paucity of stomata in the leaves indicate clearly 

 a serious feebleness of the conducting and transpiring functions 

 of those organs. Possibly, however, it may be this very 



Naturalist, 



