MANNER OF USING THE KEY AND FLORA. 



The manner of using the Key and Flora in finding the names of plants 

 will best be learned by following a few examples. Since the Dogtooth Violet 

 is one of the first to bloom in the spring, we will begin with it. 



Turn to the Key on page 7, and begin with Class I. Since our plant has 

 its ovules inclosed in an ovary, it can not be found under this class, in which 

 the plants (such as firs, pines, spruces, etc.) have naked ovules. (See Bot- 

 any, page 177, par. 127, and Figs. 93 and 94.) 



But under Class II we find the ovules inclosed in an ovary, and we see at 

 a glance that our plant belongs here under Subclass I, since the parts of the 

 flower are in whorls of three, and the leaves are parallel veined. (Compare 

 with Subclass II at the bottom of the page.) Now read after A, and if the 

 terms are not understood, look them up in the Glossary (Botany, pages 399- 

 428). Clearly our plant has a corolla, and can not come under A. Reading 

 next after B, we note that the flowers of our plant are not on a spadix and 

 are provided with two whorls of floral envelopes which may be considered as 

 calyx and corolla, and we accordingly look for it under B. (Read after C, to 

 be sure that it could not belong there.) 



Under B are three lines beginning with " Perianth," and we see that our 

 plant belongs under the second of these, which reads, " Perianth, wholly free 

 from the ovary," etc. 



Thus we are brought to the Liliacese, page 19, and we turn directly to that 

 page and read the description of the family, and finding that our plant con- 

 forms to it, we follow the key to the family to find the genus to. which our 

 plant belongs. Evidently we must hunt at once under the line " Not woody 

 climbers." The flowers of our plant are not umbellate, nor borne in racemes 

 or spikes, and so we pass at once to the third line, beginning " Flowers." 

 Reading under this line we find, " Stems leafy only at the base; flowers single 

 and erect." But our flower is not erect, and so we pass to the next line, 

 where the flower is said to be nodding. This is true of our flower, and it is 

 evidently to be looked for under Genus VII, Erythronium. 



We read the description of this genus on page 22, and find that our plant 

 belongs there. We next read the description of the two species there given 

 to determine to which of these our Dogtooth Violet may belong. 



Let us take for our next example the Maple, which also blooms early in 

 the spring. Turn again to the Key on page 7. Clearly the maple belongs in 

 Class II; and under this we find that we can pass directly to Subclass II, 

 since the stem of the maple has distinct zones of bark, wood, and pith, and 

 the calyx (the corolla is absent in the maple) is 4-5 lobed or parted. 



Under Subclass II, on pages 8, 9, and 10, we find three main divisions, 

 headed with A, B, and C. After A we read, " Corolla, and sometimes calyx, 

 wanting," while in the other divisions both calyx and corolla are present. 

 Since the corolla is lacking in the maple, we must look for it under A. ' Here 



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