xiv INTRODUCTION 



to give definiteness and accuracy. The beginner's greatest difficulty 

 is to decide just how much of a quality, such as lobing, hairiness, etc., 

 corresponds to a particular term. It is evident that practice alone can 

 give readiness and certainty in finding the names of plants, but the 

 constant use of the cuts, figures I-VI, and of the glossary, page 302, 

 will greatly reduce the practice necessary. The first plants determined 

 will inevitably take much time and patience, but the student who makes 

 sure of his facts before deciding upon each step of the key will he 

 rewarded by rapidly increasing facility in using the keys. The tend- 

 ency to guess at points of structure or at the meaning of terms must 

 be avoided at all times, if satisfactory results are to be secured. As a 

 further precaution, both of the alternative choices at each step in the 

 key must be considered, since one often throws light upon the other. 

 Finally, much time, patience and eye-sight will be saved by the use 

 of a good hand lens, magnifying 10-15 diameters and costing from 

 one to three dollars. Such lenses can be obtained from the H. W. Wil- 

 son Company, or the Minnesota Co-operative Store in Minneapolis, 

 from the Spencer Lens Company, Buffalo, or the Bausch & Lomb 

 Company, Rochester, N. Y. 



THE NAMES OF PLANTS. 



The name of a plant consists as a rule of two parts or words, for 

 example, Pinus Strobus, limits americana, Acer saccharum, etc. The 

 first word indicates the genus, and is always capitalized. The second 

 word indicates the species, or kind, and is rarely capitalized. The 

 meaning of the terms genus (plural, genera) and species (plural, 

 species) may be clearly illustrated by the pines and maples. The white 

 pine, jack pine and Norway pine are different kinds, or species, of 

 the genus of pines, Pinus, each one designated by a species name, 

 Strobus, divaricata and resinosa, respectively. The hard maple, soft 

 maple, red maple and the boxclder are different species of the maple 

 genus, Acer; they are designated by the respective species names, 

 saccharum, saccharinum, rubruni and negundo. Genera which are relat- 

 ed to each other are placed in the same family, for example, the pines, 

 spruces, firs and larches in the pine family, Pinaceae, the roses, apples, 

 plums, cherries, hawthorns, etc. in the rose family, Rosaceae. The end- 

 ing, -aceae, which is always used to denote a family, is the feminine 

 plural of the Latin suffix, -accus, meaning like or related to. The family 

 name, Rosaceae, is really an adjective agreeing with plantae, plants, 

 and meaning "plants related to the rose." Related families are them- 

 selves grouped into orders, which also bear a distinctive ending, e. g., 



