The Utricularias are the only family of those carnivorous plants that absorb decomposed matter rather than digest animal food, which have been carefully studied with reference to their functional peculiarities. The anatomy of the pitcher plants is very well known, but their physiology has yet to be learned. Darwin has subjected the glands and quadrifid processes of the utricles in this group of plants to the closest scrutiny; he has looked at them with an eye trained by a long study of other plants allied to them by their mode of life, and has shown that the glands do absorb organic matter which becomes changed within its tissues into protoplasm. The contrivances and cellular structure of our various pitcher plants leave no doubt that their mode of absorption is similar, but it is inference rather than observation upon which we have to depend in this

matter.

In 1815, Dr. McBride, a physician of South Carolina, devoted some attention to a species of very remarkable plants which grew in a marsh near his residence this was the Sarracenia variolaris, popularly called the American pitcher plant or side-saddle flower. A cluster of leaves spring from the ground: some of these are ordinary foliage leaves, while the

others have enormously developed petioles, which, curving around laterally and becoming adherent throughout their whole length, form a trumpet- or pitcher-shaped vessel, above which the leaf proper is developed.

The Heliamphora [Fig. 66], and the Sarracenia

, Petiole doubled to form pitcher; 7, leaf, rudimentary lid; w, wing, formed by non-adherent edges of petiole. [After Bentham.]

purpurea [Fig. 67], show this with perfect clearness. S. variolaris has a curved lid, formed by the bending

of the leaf around and over into a dome-like roof to

the pitcher [Fig. 68]. There are many known

A, Front; B, side view; p, petiole; w, wing; 7, leaf forming lid. [From Nature.]

species of the Sarracenia family, which do not differ

very greatly from each other;

but as S. variolaris has been most closely studied, it will be best to confine ourselves to C that, in order to illustrate the "structure. In favorable situ-r ations, with plenty of air, moisture, and sunshine, these plants spring up in great clusters, their trumpet-shaped

leaves growing from a foot to eighteen inches in height. The lid or hood, as well as a portion of the pitcher down the back, or part adjacent to the midrib, a, a, is curiously marked with white translucent spots, s; between these may be seen green or red reticulations, r. About the mouth, m, over the inner surface of the hood, h, and down the outer edge of the wing, there are seated glands which secrete honey [Fig. 69].

FIG. 68. SARRACENIA VARIOLARIS. m. Mouth; w, wing; h, hood or lid formed by leaf; a. petiole forming pitcher; c, cord; r,r, reticulations; S. diaphanous

Hooker, in describing the inner spots; 6, stem. [From Nature.]

surface of the tube, divides it into four portions. The spotted and reticulated portion, including the hood and pitcher for about an inch below the cord, c, he calls the attractive surface; it is covered with hairs, and possesses some breathing pores and many honeysecreting glands [Fig. 69]. The second surface, just below this, he calls the conductive surface; it is

Hairs a and honey glands

FIG. 69.

just inside of mouth of pitcher; the different cell arrangements of the honey glands represent different layers of glands seen at a different focus of the glass.

formed of glassy cells elongated into short conical processes which overlap each other like shingles upon a roof, and forms a very insecure foothold for insects. [Figs. 70, 72.] The third or glandular surface is also very insecure ground, and is covered with glands;