The leaves (Fig. 52, _A_, _B_) are rounded in outline unequally, two-lobed, and arranged in two rows on the upper side of the stem, so closely overlapping as to conceal it entirely. On the under side are similar but smaller leaves, less regularly disposed. The stems branch at intervals, the branches spreading out laterally so that the whole plant is decidedly flattened. On the under side are fine, whitish hairs, that fasten it to the substratum. If we examine a number of specimens, especially early in the spring, a difference will be observed in the plants. Some of them will be found to bear peculiar structures (Fig. 52, _C_, _D_), in which the spores are produced. These are called "sporogonia." They are at first globular, but when ripe open by means of four valves, and discharge a greenish brown mass of spores. An examination of the younger parts of the same plants will probably show small buds (Fig. 54, _H_), which contain the female reproductive organs, from which the sporogonia arise. [Illustration: FIG. 52.--_A_, part of a plant of a leafy liverwort (_Madotheca_), × 2. _B_, part of the same, seen from below, × 4. _C_, a branch with two open sporogonia (_sp._), × 4. _D_, a single sporogonium, × 8.] On other plants may be found numerous short side branches (Fig. 53, _B_), with very closely set leaves. If these are carefully separated, the antheridia can just be seen as minute whitish globules, barely visible to the naked eye. Plants that, like this one, have the male and female reproductive organs on distinct plants, are said to be "diœcious." A microscopical examination of the stem and leaves shows their structure to be very simple. The former is cylindrical, and composed of nearly uniform elongated cells, with straight cross-walls. The leaves consist of a single layer of small, roundish cells, which, like those of the stem, contain numerous rounded chloroplasts, to which is due their dark green color. The tissues are developed from a single apical cell, but it is difficult to obtain good sections through it. The antheridia are borne singly at the bases of the leaves on the special branches already described (Fig. 53, _A_, _an._). By carefully dissecting with needles such a branch in a drop of water, some of the antheridia will usually be detached uninjured, and may be readily studied, the full-grown ones being just large enough to be seen with the naked eye. They are globular bodies, attached by a stalk composed of two rows of cells. The globular portion consists of a wall of chlorophyll-bearing cells, composed of two layers below, but single above (Fig. 53, _C_). Within is a mass of excessively small cells, each of which contains a spermatozoid. In the young antheridium (_A_, _an._) the wall is single throughout, and the central cells few in number. To study them in their natural position, thin longitudinal sections of the antheridial branch should be made.