HOW TO USE THE POPULAK FLORA. 101 



and the petals, are five. So the plant belongs to Class I. Proceed then with the 

 " Key to the Families or Orders of Class I." on page 106. This class has two 

 subclasses. So you next ask, — 



' To which subclass does the plant belong, to Angiosperms or to Gymnosperms ? 

 For the character of the Gymnosperms, see the end of the Key, at the foot of 

 page 111 ; that of Angiospei'ms begins the Key. The centre of the flower we are 

 examining is occupied with a great number of small one-seeded pistils, each tipped 

 with its short style and stigma ; and the ovary is a closed bag containing an ovule 

 or young seed. So the plant clearly belongs to Subclass I. Proceed then with 

 the Key; which leads you next to ask, — 



To which division does the plant belong, — the Polypetalous ? (in black letters 

 immediately under the subclass), or the Monopetalous ? (top of page 109), or the 

 Apetalous? (lower part of page 110). Plainly to the first ov Polypetalous division; 

 for there is both a calyx and a corolla, and the latter is of five separate petals. 



This division, in the Key, subdivides into, " A. Stamens more than 10," and 

 " B. Stamens 10 or fewer" (p. 107). Our plant has many stamens, and so falls 

 under the head A. 



This head subdivides into three (marked 1, 2, 3), by differences as to where and 

 how the stamens are borne. Pull off the calyx and the corolla, or split a flower 

 through the middle lengthwise (as in Fig. 238), and you will plainly see that the 

 stamens stand on the receptacle, under the pistils, unconnected either with the calyx 

 or the corolla. So the plant falls under the head 1. 



Under this is an analysis of some of the characters (i. e. distinguishing marks) of 

 the fifteen or sixteen families which belong here. The lines that are set in are 

 subdivisions under the longer line above them. The lines which rank directly un- 

 der one another (and begin with the same or a corresponding word) make alter- 

 natives, among which you are to choose that with which your plant agrees. In 

 this instance the lines of the first rank here begin with the word " Pistils " or 

 " Pistil," and there are five of them. Try the first : " Pistils more than one, 

 entirely separate from each other." That is the case with our plant. Under this 

 line, in the next rank, is a triplet, or a choice between three. Our plant is an " herb, 

 with perfect flowers," and so falls under the first line. Under this is a couple 

 of equivalent lines, relating to the leaves. Our plant agrees not with the second, 

 but with the first of these ; and that line ends with the English name of the 

 family we are seeking for, viz. the Crowfoot Family, and refers to page 112, 

 where this family is described. 



