More extended descriptions and further information about these plants may be found in some of the reference books listed in the back of this booklet; many, if not all of them, are available in the Dallas Public Library. Only the more necessary technical words have been used and these are defined or illustrated herein. Although this booklet endeavors to include all the woody plants growing naturally in Dallas County, no doubt omissions and errors will be found and the author will be glad to be informed of them.
Grateful acknowledgement is made to Dr. W. M. Longnecker and Dr. E. P. Cheatum of the Department of Biology, Southern Methodist University, and to Dr. B. C. Tharp of the Department of Botany and Bacteriology, University of Texas, for their most helpful suggestions and criticisms. Although this booklet is based upon the field observations of the author and her husband, Jerry E. Stillwell, who assisted her in many ways, she has made free use of such technical information as was needed from the volumes listed in the bibliography.
The illustrations used in this publication were drawn for it by Alice Ferguson.
NORMA STILLWELL, Dallas, Texas.
Copyright 1939 by the author.
HOW TO USE THE KEY
This key is based chiefly on leaves and twigs, as they offer the easiest clues for identification, especially in this climate where leaves are present about three-fourths of the year. The best method of study is to carry this booklet to the woody plant or plants you want to know. If this is not convenient, have at least a leafy twig in hand. When collecting specimens for study (a large-paged magazine will do for carrying and pressing), notes should include the date and location, any peculiarities of the bark, nature of thorns if not on the specimen taken, color of twigs or any other features which might change in drying, flowers or seeds or any such extra clues which might help to find the right name for the plant. Small specimens of leafy twigs may be taken in suitable locations without endangering or damaging woody plants provided they are always cut, never torn from the branches.
The sizes as well as shapes of leaves are usually more typical on older plants or on the higher branches of trees. When either leaves or twigs are described as opposite, this condition will be found to be true for both, although sometimes the opposite member is missing; but leaflets (leaf-like units of a compound leaf) may sometimes be opposite when the complete leaves are not—the position of leaves, not leaflets, is used in this key. The terms rare, common or abundant are used to apply solely to Dallas County.
Begin with the numbers 1 in the key and decide which of these fits the woody plant whose name you are seeking. Turn to the key number following the 1 you have chosen and again choose between the two descriptions bearing the same number. Continue this process until you have reached the name of a plant. This name will be followed by some number above 200; turn to this number in the guide and see whether this more complete description fits. If each of your choices in the key has been correct you now know the name of your plant. If this description in the guide does not fit your plant, go over the key again, selecting this time the other choice at any number where you may have been in doubt.
Whenever it has been necessary to use an obscure or variable characteristic an effort has been made so to arrange the key that the right answer will be reached whichever the choice. That is why some plant names appear more than once in the key. If the following points are noted any careful observer should be successful in identifying the native woody plants of Dallas County by the use of this key. It will be found helpful in other regions where the native plants are similar to those of Dallas County.