HOW TO USE THE KEYS 27 



lighter green than that below, we decide that it must 

 be the new growth of the plant and that the fruit was 

 at first at the tip of the stem. We place our plant 

 under Division A because the erect stems only a Httle 

 branched, even without the fruit, bring it there. We 

 found the moss growing on the ground. Under ''Plants 

 growing on the ground" we find: "I. Shape of leaves 

 when moist not easily seen" and "II. Shape of leaves 

 when moist easily seen." The note states that the 

 leaves must be seen well enough to estimate their rela- 

 tive shape. By holding our moist specimens to the 

 light or laying them on something white, we note that 

 most of the leaves though small are easily seen to be 

 long and narrow. Our plant comes, then, under "II. 

 Shape of leaves when moist easily seen. a. Leaves long 

 and narrow." The next headings are, "Stems one-half 

 inch long or less" and "Stems more than one-half inch 

 long." The stems of our plant are not more than one- 

 half inch long, so we place it under the first of these 

 heads. The next divisions are, "Leaves hair-like 

 throughout" and "Leaves broader, sometimes ending 

 in a hair-like tip." The leaves of our plant look hair-like 

 throughout, so we read further under this head, " Cap- 

 sule erect" and "Capsule not erect." The capsules of 

 our plant are not erect, so we follow the second heading 

 to the right and come to the genus numbers i, 2, 4, 6, 

 7, 8, 26, 36. Turning to the "List of Genera" (p. 70), 

 we are referred to the page where each genus is de- 

 scribed and illustrated. Turning to number i. Trema- 



