X. INTRODUCTION. 



we shall readily perceive that the perianth has its origin below the seed 

 vessel. We pass, then, to b., on page xviii. With the first order of this 

 group it does not agree, in not having a glumaceous perianth, or being 

 " grass-like." With Melanthaceae, in not having " 3 styles." With Ponte- 

 dereae, in not having a spathe. With Asphodeleae, in the form of the 

 leaves and the testa of the seed. With Smilaceae, in the fruit not being 

 baccate. The next order is Liliaceae, with which our plant will be found 

 to agree. Under this order, there are three genera, and by noticing the 

 figures after the first genus, Lilium, wc turn to page 257, and by examining 

 the plant in relation to LiUum, Yucca and Erythronium, we shall find no 

 difficulty in determining our plant to be XheErythonium Americanum. 



Let us now take an example which will bloom later in the season. The 

 Primrose may be found every where, and is known to every body by its 

 large, conspicuous, yellow flowers. The stem is about 12-18 inches high, with 

 narrow and somewhat hairy leaves. We at once determine it to belong to 

 the Class Exogens, from its leaves, and its having bark ; and its four petals 

 show it to belong to the sub-class Polypetalae. With Section I. under 

 this sub-class, it plainly does not agree, since the stamens, so far from com- 

 ing from below the ovary, are inserted into the top of the tube of the calyx, 

 which is itself on the summit of the ovary. We pass, then, to Section II. 

 page vi., CalyciflorcB. "Stamens and petals perigynous;" that is, the 

 stamens and petals have their origin from the calyx ; this is so. Group 

 A., " Calyx superior ;" this is the case with our plant. This division is 

 sub-divided, and distinguished by small italic letters, "a., Stamens 5." — 

 This is not so. The stamens are 8. We proceed to "6., Stamens 8; Her- 

 baceous plants." This is so; but it does not necessarily follow that this 

 plant falls in this section, because it may belong to an order in which the 

 stamens vary in number. We may soon determine by reading over Melas- 

 tomacecc ; and we find that the plants of this order have opposite ribbed 

 leaves, which our specimen has not. It is not a Rhiz(yphoracecc, for they 

 are trees. It must, then, come in the division c. It is not in the order 

 Saxifragacece, for the ovaria of this order have parietal placentse, whereas 

 the placentse of our specimen are central. The next order is Onagracece ; 

 with this order it agrees. It also agrees with the first sub-order which contains 

 the genera Epilobiimi. CEnothya, Gaura, Jussisa. and Ludwigia, to one of 

 which it must belong. We now notice that the first genus, Epilobium is 

 described on page 89. We turn to this page, and by reading the descrip- 

 tion that the leaves are opposite ; flowers purple ; and that the plant grows 

 among the mountains ; all of which characteristics are obviously opposed 

 by our specimen. With the GEnothera we find it agrees, and by applying 

 the descriptions of the species to it, v?e shall find it to belong to the CE. 

 Linearis. Some of the species of this genus are found in blossom, from 

 spring to autumn and are very common. For these reasons we have cho- 

 sen this example. 

 As another example, let us take the Tread Softly, or Horse Netklc — a 



