THE CATKIN-BEARING TREES: ILLUSTRATED BY THE WALNUT, THE HICKORY, THE WILLOW, THE POPLAR, THE ALDER, THE BIRCH, THE OAK, THE BEECH, THE SWEET CHESTNUT, THE HAZEL, THE HORNBEAM, THE HOP HORNBEAM, THE PLANE TREES, THE LIQUIDAMBAR, MYRICA, COMPTONIA, CASUARINA, AND Garrya elliptica.
The plants contained in this chapter are placed by modern botanists in six or seven different orders; but I have been induced to group them together, both because they follow each other in regular succession, and because there is a certain degree of general resemblance which connects them together, and renders it easier to retain their names when linked together by the association of ideas, than it would have been if they had been each described separately.
The first order of catkin-bearing trees that I shall describe is called Juglandaceæ, and it contains three genera, only two of which, the Walnuts and the Hickories, are common in British gardens. The second order, Salicaceæ, contains also two genera, the Willows and the Poplars; the third, Betulaceæ, contains both the Alders and the Birch trees; the fourth, Corylaceæ or Cupuliferæ, contains the Oak, the Beech, the sweet Chestnut, the Hazel, and the Hornbeam; the fifth, Platanaceæ, is generally considered to include two genera; viz., Platanus and Liquidambar, though this last is, by some botanists, placed in a separate order called Balsamaceæ; and the sixth, Myricaceæ, or the sweet Gale family. All the genera included in these orders, with the exception of those belonging to Juglandaceæ, were formerly comprised in one order, which was called Amentaceæ; from the word Amentum, which signifies a catkin. The seventh and last order I have mentioned in this chapter is called Garryaceæ, and consists of one single genus, Garrya, only lately known in Europe. Of all these orders the largest and most important is Cupuliferæ, as it includes, among other valuable trees, the Oak and the Beech. All the plants mentioned in this chapter have their male and female flowers distinct, many of the genera having them on different plants; and the male flowers are always in catkins, generally long and cylindrical, but sometimes round and ball-shaped. The female flowers are sometimes in catkins also, but sometimes they are produced singly or in pairs. The flowers of both kinds are without petals, or with such as are inconspicuous; and sometimes without even a calyx, but they are always fur nished with bracts, which grow so closely to the flower as almost to seem a part of it. The ovaries are generally two-celled, but they rarely remain so, as they become one-celled before the seed is ripe. The style is, in most cases, very short, and the stigma generally two-lobed. The leaves are always alternate, and generally simple, except in the case of the Juglandaceæ. They are all hardy trees and shrubs.
JUGLANDACEÆ.—THE WALNUT TRIBE.
The genera belonging to this order have compound leaves, and the male flowers in long cylindrical catkins; the male and female flowers being on the same plant.
THE GENUS JUGLANS.
This genus consists of only three species: the common Walnut (J. regia); the black Walnut (J. nigra); and the Butter-nut (J. cinerea or cathartica). The male and female flowers are distinct, but on the same plant: the male flowers being produced in long, solitary, cylindrical catkins, and the female ones in pairs, or in shorter catkins. The leaves are pinnate, with the leaflets not always opposite, which is very rarely the case in other plants. In Juglans regia (the common walnut), the male flowers are produced in a very thick catkin, each flower consisting of
Fig. [77]—Walnut (Juglans regia). a calyx divided into five or six scale-like lobes, and generally from twelve to twenty stamens, with very long anthers and very short filaments; there is also a very curious bract to each, as shown in the magnified flower at a in fig. 77; in which the anthers are seen at b. The female flowers are in pairs, as shown at c; and they consist of a calyx, d, enclosing the ovary, and toothed in the upper part, and four small petals encircling two large thick leafy-looking stigmas, e.