Many varieties of the yew tree occur in these islands. A celebrated variety is that in which the branches are all directed upwards rather than horizontally—a frequent form of variation in trees which more usually have spreading, nearly horizontal branches. This variety is called "fastigiate" (the "fastigiate" condition of the common cypress tree is the one usually cultivated, although there are common varieties with spreading branches), and in the case of the fastigiate yew it is accompanied by a variation in the disposition of the needles or leaves. Instead of being carried right and left in a single row on each side of the young branches, as is usual with yews, the needles are set all round the branch in spiral order (as they are in many conifers). This variety was found growing wild in Co. Fermanagh, Ireland, nearly two hundred years ago, and a couple of trees of it were then cultivated at Florence Court by the Earl of Enniskillen of that date. Thousands of cuttings have been sent from one of these two original trees, which is still vigorous (I saw it some thirty years ago at Florence Court) all over the world. It is known as the "Florence Court yew," or "Irish yew," and is commonly planted in gardens. But all are from cuttings of this one original tree, or cuttings of its cuttings, and all, like their parent, are female berry-bearing trees, for the male and female flowers grow on separate trees in the yew.
The foliage of the yew contains aromatic and other chemical products, which render it poisonous to cattle. It is said not to be poisonous when quite fresh, but only some time after cutting. This, however, needs confirmation. The yew makes an admirably compact and impervious screen when grown as a hedge, and has been largely used in gardens for this purpose. In the sixteenth century it was the custom to clip yew hedges, or small yew trees, into all sorts of strange shapes, birds, beasts, and crowns. The name "topiary" is given to this fanciful work. The popularity of the yew in the gardens of those days is due to the small number of our native evergreen shrubs and trees; they are yew, Scots fir, juniper, holly, privet, ivy, butcher's broom, box (a doubtful native), spurge-laurel, and mistletoe. Up to the end of the seventeenth century only a few evergreens had been introduced from abroad, viz., spruce pine, silver fir, stone pine, pinaster, the cedar of Lebanon, savin, arbor vitæ, evergreen oak, sweet bay, Portugal laurel, laurustine, and arbutus.
I have often wished to have some simple, straight-forward information as to conifers, so as to be able to know what differences among them are really recognized by botanists, and what are the correct names of those which one commonly sees. Having gathered that information, I propose to impart it, as far as may be consistent with brevity, to my readers, though I am afraid that to some it will prove a dull business. The order Coniferæ, from which the yew trees (Taxaceæ) are excluded, is divided into four families. These are: (1) the family Abietinæ, which comprises the true pines, and fir trees, and the cedars; (2) the family Araucarianæ, which includes the Monkey puzzle of South America and Australia, and the Dammar tree of New Zealand; (3) the family Taxodinæ, which is best known by the so-called Wellingtonia, or Sequoia, but includes several other genera and species; and (4) the family Cupressinæ, in which the juniper, cypress, and "arbor vitæ," or Thuya, are placed.
The form and size of the frequently needle-like leaves of coniferæ are not of so much importance in indicating the affinities of these plants as one might expect, although their grouping either in tufts or in rows is a matter of significance. In some of them the "needles," or leaves, are long and narrow (Abietinæ); in others they are broad and leaf-like (Araucarianæ); in others they are all or most of them reduced to mere ridges or short scales set quite closely to the leaf-bearing branch (many Cupressinæ and Taxodinæ). It is not possible to give, without going into botanical minutiæ, the items of structure by which the four families of conifers are distinguished from one another. It is best for the nature-lover who is not an adept in botanical details to think of them as grouped each round one well-known species. Thus the Abietinæ are grouped round the spruce pine, the Araucarianæ round the monkey puzzle, the Taxodinæ round the Wellingtonia, and the Cupressinæ round the juniper. In all but the last family the ovule-bearing scales of the female cone are arranged spiral-wise around a central supporting stem; in Cupressinæ they are few in number, very thick, and opposite to one another so as to form a globular rather than a cone-shaped body. In all but a few Cupressinæ and Araucarianæ the male and female cones are carried on the same tree, sometimes on separate branches, but usually on the same branch. The male and female cones are always distinct, and the female much the larger and more enduring.
Fig. 33.—A thin slice across one of the foliage needles of the Common Spruce. Highly magnified. r, The single resin canal; f, the mid-rib, with a single bundle of fibres and vessels cut across.—(From Veitch.)
Fig. 34.—A thin slice across one of the foliage needles of the Silver Fir. Highly magnified. It is flatter than the similar slice of the needle of the spruce. r, r, The two resin canals; f, the mid-rib, in which two bundles of fibres and vessels can be distinguished.—(From Veitch.)
The Abietinæ are divided into three tribes—(a) the spruces and silver firs (this group corresponding to the French Sapins), (b) the larches and cedars, (c) the Scots firs (Pins of the French). Let us take first the group of spruces and silver firs. The Norwegian spruce is the type of the genus Picea. It is called Pesse by the French, Fichte by the Germans, and Picea excelsa by botanists. We may contrast it with the silver fir Abies pectinata (Sapin des Vosges of the French, Silbertanne of the Germans), which we take as the type of the genus Abies. In many respects the silver fir looks like the spruce. In both the stem is straight, reaching a height of 100 to 150 feet, regularly furnished with tiers of branches from the ground upwards. The leaves are needles, half an inch to an inch long, which stand out from the branchlets, but in the spruce they are quadrangular, green all over, and arise all round the branch, whilst in the silver fir they are flat, grooved on the lower surface, which is silver-grey in colour, and they tend to be disposed right and left in two rows. Each needle has a single resin canal in the spruce, but has two in the silver fir, as may be easily seen by cutting the needles across the length with a sharp knife (Figs. 33 and 34). Each scale-like ovule-producing leaf which goes to build up the ripe seed-bearing cone has (as in all conifers theoretically) an outer scale, called a "bract," attached to it which is very short and hidden in the case of the spruce cone, but is longer than the ovuliferous scale, and very obvious in the silver fir (Fig. 35). It has a triangular re-curved point, which gives the cones of that species a characteristic appearance (Fig. 36). The cones of the silver fir (5 to 6 inches long and 2 inches thick) are set upright on the branches, and when they have shed the seeds the scales fall off rapidly and leave the axis bare, whilst the cones of the spruce (about an inch shorter) are pendulous (Fig. 37), and their scales remain in position after the seed is shed.
