16 



Introduction 



Here again many families bear descriptive names as Umbellif erae 

 where all the flowers are in umbels, and Rosaceae where all 

 flowers bear a strong resemblance in structure to the wild rose. 



It will thus be seen that all plants are individuals, and as 

 such are entitled to as much respect in nomenclature as do the 

 highest organisms of the animal kingdom. 



HOW TO USE THE KEY 



The method of finding the name of a plant by means of a 

 key is best illustrated by a definite example. First, turn to the 

 key on page 17. The first choice to be made is between plants 

 with leaves and plants without leaves. 



Suppose we take the common agarita. Under plants with 

 leaves, you will find a choice between I. Leaves compound (page 

 17) and II. Leaves simple (page 25). The agarita has compound 

 leaves. Under I. Leaves compound, make a choice between A. 

 Leaves palmately compound (page 17) and B. Leaves pinnately 

 compound (page 18). Having decided on A. Leaves palmately 

 compound, the investigator's next decision rests between 1. Leaf- 

 lets generally 3 (page 17) and 2. Leaflets usually 5 (page 18). 

 Our plant has 3 leaflets, so take choice 1. Under choice 1., choose 

 between a. Flowers yellow and b. Flowers white. The flowers of 

 the agarita are yellow. Under a. Flowers yellow, take choice 

 x. Shrub, leaflets 3, spine-toothed, which will take you to Berberis 

 v{page 82). Now turn to page 82, where the family, genus, 

 species, common name and description are given. 



Where both the calyx and corolla are not present, call the parts 

 given calyx, regardless of whether they are colored and corolla-like 

 or not 



The measurement of plants in Texas does not always agree with 

 those given in the textbook descriptions due to the variability of our 

 seasons. In a drought year plants may be only a few inches high, while 

 in the following season with plenty of rainfall they will have a rank 

 growth shoulder-tall. Likewise blue and pink flowers often have 

 albino forms. Albino forms are common in the shrubby sage, Erythraea. 

 Sabbatia, baby blue-eyes, and violets. 



