The central circle of leaves, the carpels (collectively the "gynœcium") are completely united to form a compound pistil (Fig. 81, _E_). This shows three distinct portions, the ovule-bearing portion below (_o_), the "ovary," a stalk above (_st._), the "style," and the receptive portion (_z_) at the top, the "stigma." Both stigma and ovary show plainly their compound nature, the former being divided into three lobes, the latter completely divided into three chambers, as well as being flattened at the sides with a more or less decided seam at the three angles. The ovules, which are quite large, are arranged in two rows in each chamber of the ovary, attached to the central column ("placenta"). The flowers open for several days in succession, but only when the sun is shining. They are visited by numerous insects which carry the pollen from one flower to another and deposit it upon the stigma, where it germinates, and the tube, growing down through the long style, finally reaches the ovules and fertilizes them. Usually only a comparatively small number of the seeds mature, there being almost always a number of imperfect ones in each pod. The pod or fruit (_F_) is full-grown about a month after the flower opens, and finally separates into three parts, and discharges the seeds. These are quite large (Fig. 81, _J_) and covered with a yellowish brown outer coat, and provided with a peculiar, whitish, spongy appendage attaching it to the placenta. A longitudinal section of a ripe seed (_K_) shows the very small, nearly triangular embryo (_em._), while the rest of the cavity of the seed is filled with a white, starch-bearing tissue, the endosperm. [Illustration: FIG. 82.--_Erythronium_. _A_, a portion of the wall of the anther, × 150. _B_, a single epidermal cell from the petal, × 150. _C_, cross-section of a fibro-vascular bundle of the stem, × 150. _tr._ vessels. _D_, _E_, longitudinal section of the same, showing the markings of the vessels, × 150. _F_, a bit of the epidermis from the lower surface of a leaf, showing the breathing pores, × 50. _G_, a single breathing pore, × 200. _H_, cross-section of a leaf, × 50. _st._ a breathing pore. _m_, the mesophyll. _fb._ a vein. _I_, cross-section of a breathing pore, × 200. _J_, young embryo, × 150.] A microscopical examination of the tissues of the plant shows them to be comparatively simple, this being especially the case with the fibro-vascular system.