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Key to Species — Part 30

A. Flowers yellow; leaflets 5 to 7.

B. Husk spiny or rough; stamens long.

(AE. glabra) OHIO BUCKEYE

BB. Husk smooth; stamens short.

(AE. octandra) SWEET BUCKEYE

AA. Flowers white; leaflets 5.

B. Fruit smooth, pear shaped.

(AE. Californica) CALIFORNIA BUCKEYE

BB. Fruit spiny, globose. (Exotic.)

(AE. Hippocastanum) HORSE CHESTNUT

AAA. Flowers red; leaflets 5; fruit smooth.

(AE. austrina) BUCKEYE

There are but few of our native tree families whose leaves are set opposite upon the twigs. The horse chestnut family is one of them. This is an important family trait, wherever it occurs; it is shared by the ashes, maples, dogwoods, catalpas, viburnums and elders. Of these six the first and last have compound leaves. So a tree with opposite and compound leaves, if a native, is almost sure to be an ash, an elder or a buckeye. Ash and elder leaflets are always distributed in pairs along the sides of the main leaf stalk. The buckeyes all bunch their leaflets at the end of the leaf stem. They are palmately compound, while those of the ash are pinnately compound. This simple and easy mode of identifying opposite-leaved trees is set forth more graphically in the Key to the Families.

Buckeyes are distinguished by large winter buds, showy flowers in pyramidal racemes, large handsome foliage, and large nuts in 3-valved husks.

Every continent of the Northern Hemisphere has its buckeyes. There are eleven species in all. Of these America has four in her own right; the horse chestnut of Asia Minor is much oftener planted in this country than the native kinds. Indeed this species is the most cosmopolitan of trees, being found in the parks of cities in all regions where the climate permits it to thrive. It is a hardy immigrant, springing up spontaneously in some sections of our Eastern States.

The name "buckeye" is traceable to the brown nut marked with white, which suggested to somebody's fancy the eye of a deer. "Horse chestnut" employs the word horse to indicate that the fruit, which resembles the familiar edible chestnut, is unfit for human food. One nibble will prove to anyone its rank quality. These nuts lie untouched by squirrels through the most trying of winters. A strange circumstance is that the name AEsculus was the classical name of an oak tree, and it is very similar in form to the Latin word which means edible. Acorns formed an important part of the diet of primitive peoples, but it is hard to imagine an edible horse chestnut. Bitter, astringent bark and seeds are characteristic of the whole family.

In Mexico and Central America grow two species of the genus Billia, trees with three leaflets instead of five or seven. Otherwise, the trees are like the buckeyes, and are included in the family. The maples with their opposite leaves are near relatives of the buckeyes.

Ohio Buckeye, Fetid Buckeye (AEsculus glabra, Willd.)--Tree 20 to 70 feet high, with small, spreading top; odour fetid; twigs brown, pubescent, becoming smooth. Bark grey, broken into plates. Wood white, shading into brown sap wood, light, soft, and difficult to split. Winter buds pointed, 2/3 inch long, not resinous; scales elongating to 2 1/2 inches in spring, becoming light coloured. Leaves opposite, yellow-green, of 5 (rarely 7) obovate, smooth leaflets. Flowers April and May, in terminal clusters, small, pale, yellow-green. Fruit, October, 1 to 1 1/2 inches in diameter, globular, 3-valved, very prickly when green, becoming less so when ripe; nut brown, with pale spot on side. Preferred habitat, moist woods along river banks. Distribution, Alleghany Mountains from Pennsylvania to Alabama; west to Michigan and Oklahoma. Uses: Wood used for artificial limbs and small wares.

This tree was found most abundantly in Ohio by the botanical explorer, Michaux, and though it grows more plentifully farther west, Ohio will always be called "the Buckeye State." The tree is gradually becoming rarer, for the strong, disagreeable odour exhaled by its bark impels people to cut it down. There is nothing about the tree to offset this disadvantage. Its flowers are inferior to those of other species. Only the special use to which its wood is put--the making of artificial limbs--seems to justify this ill-favoured tree in the eyes of practical people. Its vigorous nuts are too bitter to be eaten, and thus it seems to be well fitted to hold its own in the woods.

The Yellow, Sweet, or Big Buckeye (AEsculus octandra, Marsh.), grows on mountain slopes of the Alleghanies, from western Pennsylvania south into Georgia and Alabama, and west to Iowa and Texas. It is a handsome large tree, with leaves of five slenderly elliptical leaflets, more or less pubescent below and on the veins above. The showy yellow flowers are elongated into tubes. The husks of the nuts are smooth. This species lacks the disagreeable odour of the Ohio buckeye, and its nuts, though distasteful to people, are eaten by cattle. Paste made from these nuts is preferred by bookbinders. It is strong in two senses: it holds well, and destructive insects will not eat it.