226 THE FLO-WER. 



ground, they assume the asjject of creeping roots, and sometimes 

 form thickened rootstalks, as in the Calamus and Solomon's Seal, or 

 tubers, as in the Potato. But the type is readily seen through 

 these disguises. They arc all mere modifications of the stem. The 

 leaves, as we have alretidy seen, appear under a still greater variety 

 of forms, some of them as widely different from the common type of 

 foliage as can be imagined ; such, for example, as the thickened and 

 obese leaves of the Mesembryanthemums ; the intense scarlet or 

 crimson floral leaves of the Euchroma, or Painted-Cup, of the 

 Poinsettia of our conservatories, and of several Mexican Sages ; the 

 tendrils of the Pea tribe ; the pitchers of Sarracenia (Fig. 300), 

 and also those of Nepenthes (Fig. 301), which are leaf, tendril, and 

 pitcher combined. The leaves also appear under very different 

 aspects in the same individual plant, according to the purposes they 

 are intended to subserve. The first pair of leaves, or cotyledons, 

 when gorged with nutritive matter for the supply of the earliest 

 wants of the embryo plant, as in the Almond, Bean, Pea, &c. (Fig. 

 108-120), would seem to be peculiar organs. But in some of 

 these cases, when they have discharged this special office in ger- 

 mination, by yielding to the young plant the store of nourishment 

 with -which they are laden, they imperfectly assume the color and 

 appearance of foliage ; while in other cases, as in the Convolvulus 

 (Fig. 123) and the Maple (Fig. 104), they are green and foliaceous 

 from the first. As the stem develops, the successive leaves vary in 

 form or size, according to the varying vigor of vegetation. In our 

 trees, we trace the last leiu-es of the season into bud-scales ; and in 

 the returning spring we may often trace the scales of opening buds 

 through intermediate states back again into true leaves (161). 



426. The analogies of vegetation would therefore lead us to ex- 

 pect, that in flowering the leaves would be wrought into new forms, 

 to subserve peculiar purposes. In the chapter on Inflorescence, we 

 have already learned that the ari-angement and situation of flowers 

 upon the stem conform to this idea. In this respect, flowers are 

 absolutely like branches. The aspect of the floral envelopes favors 

 the same view. We plainly discern the leaf in the calj^x, and 

 again, more delicate and refined, in the petals. In numberless in- 

 stances, we find a regular transition from ordinary leaves into sepals, 

 and from sepals info petals. And, while even the petals are occa- 

 sionally green and herbaceous, the undoubted foliage sometimes 

 assumes a delicate texture and the brightest hues (425). The per- 



