EXPLANATION OF THE FLORA 281 



the "genus cover." Its size when folded is ll%xl6% 

 inches. On the lower left-hand corner the name of the 

 genus is written. If one has many sheets in one genus 

 — say more than 20 — it may be necessary to have more 

 than one cover for them. The covers are laid in cup- 

 boards flatwise, one on the other, and the sheets then 

 retain their shape and are always ready for use. 



EXPLANATION OF THE FLORA.— The following flora con- 

 tains 025 species of plants in 294 genera and 51 families. 

 These species are selected from common and representative 

 plants, in the hope that 50 to 100 of them may be secured 

 by any pupil. The pupil should collect his own specimens 

 as far as possible, and he should press and preserve them 

 after he has studied the structure. Familiarity with 100 

 plants will give the pupil a good grasp of plant forms, 

 provided he does not stop with merely acquiring the names 

 and pressing the specimens. He should know how the 

 plants look, where they grow, how they associate with 

 other plants, how long they live, and the like. 



Avoid the use of keys as much as possible: learn to 

 see the plant as a whole: go directly to the family, if 

 possible. But it may be necessary to use keys at first. 

 In this book coordinate parts of the key are marked by 

 the same letter: e.g., f, ff, fff, are three coordinate 

 entries. Coordinate entries are also introduced by the 

 same catch-word, as "flowers," "leaves," "fruit." Using 

 a key is a process of elimination. First try the plant in 

 A; if it does not belong there, go to aa. Then repeat 

 the search in b, bb, etc., until the family is found. 



Synonyms are placed in parenthesis itn mediately fol- 

 lowing the accepted name. Thus "Impatiens biflora, 

 Walt. (7. /»ii'fl, Nutt.)" means that the accepted name is 

 Walter's I. biflora, but that the plant is also known by 

 Nuttall's name, I. fulva. 



Proper pronunciation is suggested by the accent, which 



