2 KEY AND FLORA 
the genus has been reached, presents no difficulty in a little 
flora like the present one. 
A single example may suffice to illustrate more in detail 
the manner of determining species. Suppose the student to 
have in hand a flowering specimen of lily of the valley. Turn- 
ing to the key, page 5, it is evident from the statements con- 
cerning Gymnosperms that the plant does not belong under 
that head. Under Angiosperms it is clear, from the numerical 
plan of the flower (in threes) and the parallel-veined leaves, 
that the plant is a Monocotyledon. Among Monocotyledons 
three general groups are designated by as many numbers in 
parenthesis. The flower in hand belongs under (3) “ Flowers 
not on a spadix.”” Under this head the choice is first be- 
tween (a) “Carpels numerous and separate” and (0) “ Carpels 
united.” In the lily of the valley they are united. The next 
choice is between “*Perianth hypogynous” and “** Peri- 
anth not hypogynous.” This flower is hypogynous. The 
families with hypogynous perianth are grouped under three 
divisions (distinguished by f, ft, ttf respectively), and of 
these the last, with its “Perianth actinomorphic, its divi- 
sions all alike or nearly so, petal-like,” corresponds to the 
flower under examination and refers the student to “10. Lily 
Family, page 6.” Turning to the key to the genera of the 
Lily family, page 31, two subfamilies are found. Since the 
plant is not a climber it belongs to “Subfamily I. Liliacee 
Proper.” 
This subfamily is divided into five groups designated by 
capital letters. The lily of the valley has an undivided style 
and springs from a rootstock, therefore it belongs to group B. 
Reading the descriptions under B, none is found to agree with 
the plant in hand until the next to the last is reached: “ Leaves 
only 2, directly from the rootstock. Flowers in a raceme, bell- 
shaped, white, sweet-scented, Convallaria.” 
