A tree reaching over 100 ft in height, with a rounded, spreading head as much in diameter, and a trunk 15 ft or more in girth; winter buds very resinous. Leaves composed of five to seven leaflets, which are obovate, from 5 to 12 in. long, 2 to 5 in. wide, irregularly toothed, the terminal one the largest; the upper surface is glabrous, the lower one has patches of brown hairs in the axils of the veins, and short hairs thinly scattered over it. Panicles up to 12 in, high, and 4 in. through. Flowers with four or five petals, white with a patch of colour at the base, which is at first yellow, then red; stamens rather longer than the petals. Fruit spiny, 21⁄2 in. across, containing one, sometimes two, of the well-known lustrous brown nuts.
The horse-chestnut is at once the best-known and the most beautiful of flowering trees of the largest size. The stately, spreading form of fully grown trees is appropriately accompanied by noble proportions and handsome shape of leaf, and by large, striking flower-clusters. An English park can afford no finer sight than a group of horse-chestnuts towards the end of May, when every branchlet carries its erect cone of white flowers. The history of the horse-chestnut is interesting. It reached Western Europe by way of Constantinople in 1576, when seeds were sent to the botanist Clusius at Vienna, and it had spread westwards to France and England early in the seventeenth century. For more than two hundred and fifty years its real native country was unknown. N. India was long regarded as its most probable home, and Loudon, as late as 1837, suggested N. America. Its real wild habitat is now definitely established as being much nearer home; namely, in the mountainous, uninhabited wilds of Northern Greece and Albania, where several observers have found it to be undoubtedly indigenous.
The economic value of the horse-chestnut is not great. The timber is soft and lacking in strength, and is chiefly employed in the manufacture of kitchen utensils, toys, and other articles for which durability is not of great importance. The nuts are abundantly produced, and are eaten by some animals, notably deer. I have noticed the deer in Bushey Park, at the time the nuts are falling, race eagerly for them as they drop to the ground. Loudon and others suggest various uses for them, but so far as I can learn there is no systematic demand for them. They have such an extraordinary fascination for boys in furnishing the material for the game of ‘conkers’ (conquerors), that the value of the species as a communal tree is in some districts seriously diminished by their efforts with sticks and stones to bring down the nuts before they naturally fall.
cv. ‘Baumannii’. – A form with double flowers. According to A. N. Baumann, it was noticed by him as a sport on a tree of the ordinary type growing in the garden of a Mons. Duval, near Geneva, during the years 1819 to 1822. He sent grafts to his father’s famous nursery at Bollwiller, in Alsace, whence it spread into cultivation. Its flowers last longer than those of the type, and as no nuts are formed the tree escapes the danger of injury just alluded to. For public places it is strongly recommended, and is the best of the garden varieties. It has also been called A. h. flore pleno.
cv. ‘Crispa’. – A tree of compact, rather pyramidal habit, with short, broad leaflets. Listed by Booth’s nursery, Hamburg, 1838.
cv. ‘Digitata’. – Leaflets short, narrow, often reduced to three, of linear shape; the main-stalk frequently very markedly winged. An old variety, no longer at Kew, said to have originated in France (var. pumila Dipp.).
cv. ‘Henkelii’. – Leaflets smaller than in the type, with shreddy margins. The plant at Kew was bought from Henkel’s nurseries in 1904. The A. h. incisa put into commerce by James Booth of Hamburg before 1838 was probably similar.
f. laciniata (Jacques) Schelle – Leaflets very narrow, deeply incised. There are several forms of this nature, of independent origin. The clonal name ‘Laciniata’ belongs to one found near Angers around 1844 and put into commerce by Leroy. Another was in commerce in Loudon’s time as A. h. aspleniifolia. The form grown at Kew is an extraordinary curiosity of little beauty, whose leaflets are sometimes nine in number, but often reduced to the mere midrib with jagged remains of blade attached; it was received from Simon-Louis Frères in 1900.
cv. ‘Memmingeri’. – Leaves pale greenish or greyish, yellow when they first expand. Of no merit. First described in 1855.
cv. ‘Pyramidalis’. – Branches growing upwards at an angle of 45° to the main stem. This would probably be useful as a street tree, and avoid to a large extent the drastic pruning so often practised to keep the ordinary form within bounds. There are two trees of this habit at Kew, apparently of the same clone. One was received from Späth in 1895 and the other from Transon in 1896.
cv. ‘Umbraculifera’. – A form with a low, dense, rounded head of branches. In cultivation since 1884, but origin unknown. A fine example grew earlier in this century in the nursery of Messrs Simon-Louis near Metz.
A form which breaks into leaf and flower ten to fourteen days in advance of the ordinary one was represented at Kew earlier this century by two large trees which no longer exist. The name under which they were listed – A. h. praecox – appears in the catalogue of James Booth and Sons, Hamburg, in 1838. There is, it should be added, still one tree at Kew, part of a row of thirty, that breaks into leaf a week or ten days earlier than the others, and also flowers earlier, but its origin is unknown.
Forms with white- or yellow-variegated leaves were in commerce in this country as early as 1775, but are only to be seen in old collections. One with yellow-blotched leaves was described in previous editions as ‘a variety to be avoided’.