THE TREE FAMILIES. It is quite possible for a person who has never had any par ticular interest in trees to acquire by himself a general knowledge of the tree families represented in our American forests, and to form an intimate and delightful acquaintance with particular species and individual trees, as his personal preferences dictate. And it is not to be undertaken as a herculean task, a duty to be performed, a means of grace, or an ill-tasting medicine that does one good. True, there are half a hundred families or more, and over six hundred distinct species of trees, if we wander from Key West to the far Aleutians, and from Maine to Mexico, and count every species any botanist has discovered and named. But the average forest contains comparatively few families. Different families have traits in common that indicate their relationship. Within the family closer kinship still is revealed.
The discovery of these family ties and family groups comes easy and as naturally as breathing, once it is begun. The neces sary botany is unconsciously imbibed. One borrows that from the books as need is. Every acorn-bearing tree is an oak. The needle leaves set in scaly sheaths at the base distinguish the pines from all other evergreens. The hickories have close rela tives in all the nut trees. The sycamores have no near relatives at all. The willows and poplars are alike in catkin flowers and fluffy seeds. All locusts bear pods.
The key that follows is a simple tool. It unlocks mysteries that are largely imaginary as to the common tree families by setting them forth in brief, descriptive terms, giving a bird's-eye view of them, and emphasising their chief points of similarity and difference. Botanical terms have been avoided, and such characters selected as shall be obvious to the inexperienced observer.
The plan of construction is easily grasped. A and AA are the two grand divisions into which trees naturally fall. Being co-ordinate, these have the same letter of the alphabet, and are set on the extreme left margin of the page. The second has an added letter; if there were a third division it would have three A's. The subdivisions of A are always B, BB, etc., according to their number. B is divided into C, C into D, and so on down the list. In every instance co-ordinate letters are set at the same distance from the left margin, forming a vertical line down the page. They are also grouped by their "catch words"—as will be seen.
A includes the chief families of the evergreens. Under A are two groups, B and BB, based upon the character of the fruit. Under B there are two subdivisions, based upon the general shape of the leaf. The cone-bearing evergreens, B, show two types of foliage, described under C and CC. The former is divided into three groups, D, DD, and DDD, on "Arrangement of leaves." The catch word of B and BB is "Fruit"; of C and CC, "Foliage." D and DD each describes a family; DDD includes more, and must be subdivided. E and EE are the headings and " Leaves" the catch word. E contains F and FF, based on the cones and
other characters. EE, CC, and BB are undivided, as each describes a single family.
The next step is to learn how to use the key. It is worthless unless it unlocks closed doors and reveals hidden things worth finding. Go out with the key and approach the first evergreen in sight. It belongs in the group A, your common sense tells you. Very well. Which B does it agree with ? Look for signs of fruit on and under the tree. Are they cones or berries ? Cones? Then this tree belongs in B. All right. Is its foliage needle-like, etc., or scale-like—C or CC ? Needle-like. Now you must study the arrangement of leaves on the twigs, and decide which one of the three D's fits. Perhaps the leaves are solitary and scattered. Still closer study of them is necessary. If they agree with EE you know that the tree is a spruce.
Suppose at the start your tree has borne blue berries instead of cones. You would have dropped to BB at once and found your tree to be a juniper.
Now the beauty of a key is that you so soon outgrow the need of it. There are seven great families of the native ever geens. To make it as simple as possible, the rare and local evergreens, like the sequoias, the bald cypress and the yews, have been omitted. It should take but a single encounter with a tree to run it down to its family in the key. The intentness of this exercise will fix on the mind the characters that distinguish the family. You find yourself rolling a leaf between thumb and finger to see if it has the four sharp edges that set the spruces apart from all the others. Or you look intently for the tiny leaf stern of a pale-lined flat leaf; to know whether it is a hemlock or a fir.
In the grand division AA the broad-leaved trees are set in their proper families. There are more of these than of the ever greens. They are best studied while leaves are to be had for identification. Often the seeds remain in winter, and we can get on with only the evidence of dead leaves. There are few weeks in the year when the key may not be effectively used on any tramp in the woods.
As in the evergreens, the local and rare families of broad leaved trees have been omitted, that the key may not discourage beginners by its complexity. In all, the thirty-three families given include between four and five hundred species, and a large proportion of those left out are esteemed chiefly by the botanists. Many of these will be found described later in this book.
The key to the families introduces the reader to the more intricate distinctions between trees of various genera and species in the family. The keys to species are made on the same plan. Having determined that a certain tree belongs to the maple family, the inquirer is able to turn to "The Maples," and by the key to decide which of the various species this individual tree represents. This is the final end of any key—to lead the student to discover the name of the individual tree.