TREES AND SHRUBS. 405 



ring-like cushion (nectary), the hairy flattened ovary (two 

 chambers each with two ovules), and the short style with 

 two curved stigmas. As a rule the central flower in each 

 group has a fully developed pistil, and eight stamens with 

 short filaments, but the anthers (though containing pollen) 

 do not open, so that the flower is practically female. The 

 other flowers are male, having eight to twelve stamens with 

 long filaments, and a small sterile pistil. Sometimes a whole 

 inflorescence consists of these male flowers ; in all cases the 

 male flowers appear to mature before the female flowers. The 

 flowers are visited by insects, chiefly bees and flies. 



The fruit has two spreading and diverging wings, one pro- 

 duced from the outside of each chamber or half -fruit. Each 

 chamber contains a large rounded seed (Art. 79). 



[393. Horse Chestnut (Aesculus hippocastanum) is a large 

 tree (about 60 ft.), with erect trunk and pyramidal head ; it 

 is a native of Asia and North America and was introduced 

 into Britain about 1630. The name is derived from the re- 

 semblance of its seeds (too bitter for human food, though 

 eaten by various animals) to the edible fruits of Sweet 

 Chestnut, " horse " being a contemptuous prefix meaning 

 coarse, as in Horse Eadish, or as " dog " in Dog Violet, etc. 



The twigs are thick, the buds (Art. 178) large, brown, and 

 sticky ; the branches ascend at first, then bend downwards 

 and often curve up again at the ends. The bark is smooth 

 for many years, but later becomes grooved and scaly. The 

 leaves are in crossed pairs. As in Sycamore, the leaves differ 

 according to their position on the branches, the lower ones 

 having larger blades and larger stalks, but the mosaic is made 

 more perfect by the fact that the leaves are compound, so 

 that the individual leaflets can vary in shape and thus 

 catch the light more fully. 



The leaf-stalk has a broad base and is also broadened at 

 the top where the leaflets (5 to 9, typically 7) come off. 

 The leaflets themselves have no stalks ; each has a sharp 

 tip, just below which the leaflet is broadest, and a toothed 

 edge. On a horizontal branch the lower buds either remain 

 dormant or grow into small and short-lived twigs. When 

 the inflorescence eventually falls off from the end of a 

 flowering twig, a saddle-shaped scar is left, and the onward 



