2IO The Trees of Great Britain and Ireland 



^SCULUS HIPPOCASTANUM, Common Horse-Chestnut 



^sculus Hippocastanum, Linn^us, Sp. PL 344 (i7S3); Loudon, Arb. et Fmt. Brit. i. 462, iv. 2543 

 (1838); Card. Chron. 1881, xvi. 556, figs. 103, 104. 



A large tree, attaining in England a height of over 100 feet and a girth of 15 

 or even 20 feet. Bark smooth and dark brown in young trees, becoming greyish and 

 fissured longitudinally in old trees, at the same time scaling off in thin plates. 

 Leaves palmately compound, digitate, on a long stalk widened at its insertion. 

 Leaflets five 'to seven, sessile, obovate, cuneate at the base, abruptly acuminate 

 at the apex, unequally and coarsely serrate ; green above ; beneath pale, tomentose 

 at first, but ultimately glabrous, except for small tufts of hairs in the axils 

 of the veins and a few scattered hairs over the surface ; middle leaflet the 

 largest, with twenty-four or more pairs of nerves, lower pair smallest ; venation 

 pinnate ; petiole glabrous. The leaflets as they emerge from the bud are at first 

 erect, but soon bend downwards on their stalks. When nearly full grown they 

 rise up and become horizontal. In autumn they turn yellow or brownish and fall 

 early, each leaflet disarticulating separately from the petiole. 



Flowers in large upright pyramidal panicles, the primary branches of which are 

 racemose, the lateral branches cymose. Upper flowers staminate and opening first ; 

 lower flowers hermaphrodite. Calyx greenish, five-toothed. Petals four to five, 

 crumpled at the edge, white, with yellow spots at the base, which ultimately 

 become pink. Stamens seven, longer than the petals, the filaments bent down when 

 the flower opens and the stigma protrudes, later moving up on a level wath the 

 style. Fruits few on each panicle, large, globular, green, with stout, thick conical 

 spines, three-valved, usually one-seeded, occasionally two- to three-seeded. Seed 

 large, shining-brown, with a broad whitish hilum. Cotyledons two, large, fleshy, 

 distinct below, blended into one mass above. 



Seedling^ 



The cotyledons are large and fleshy and remain in the seed, which frequently 

 germinates on the surface of the soil or only slightly buried beneath it. The 

 cotyledons have long petioles (f-i inch), which are broad and flattened, with a 

 concavity on their inner surface. The caulicle, very variable in length (i to 4 inches), 

 is stout, brownish, pubescent, and ends in a stout tap-root, which gives off numerous 

 branching fibres. The young stem is stout, terete, brownish, striated and marked 

 with numerous lenticels, puberulent or glabrous ; it has no scale-leaves, differing 

 in this respect from the young stem of the oak. In other respects the germination 

 of the oak and of the horse-chestnut are almost identical. At a varying height 



1 Cf. Lubbock, Seedlings, i. 356 (1892), where it is stated that the seed is carried a considerable height above ground 

 during germination owing to the great length of the caulicle. So far as I have observed, the seed does not change its position 

 during germination. 



