. Nature and development of plants. Botany. 274 REPRODUCTION OF RICCIOCARPUS cells or glands. The development of these glandular cells on the plates, as well as on the other parts of the thallus, adapt the plants to the drier terrestrial conditions to which they are exposed, as was the case with the mucilaginous walls of the Schizomycetes and Zygnematales. (b) Sexual Reproduction of Ricciocarpus.—The gametes are produced in more complex gametangia than we have as yet seen. These organs are developed upon the upper surface of the thallus. Fig. i8i. The origin and structure of the male gametangi
. Nature and development of plants. Botany. 274 REPRODUCTION OF RICCIOCARPUS cells or glands. The development of these glandular cells on the plates, as well as on the other parts of the thallus, adapt the plants to the drier terrestrial conditions to which they are exposed, as was the case with the mucilaginous walls of the Schizomycetes and Zygnematales. (b) Sexual Reproduction of Ricciocarpus.—The gametes are produced in more complex gametangia than we have as yet seen. These organs are developed upon the upper surface of the thallus. Fig. i8i. The origin and structure of the male gametangia or antheridia: A, section of the thallus, showing the apical cell, x, and the early stages, a, b, in the development of the antheridia. B, older antheridium with cells dividing vertically. C, later stage in which the wall cells are differentiated. D, mature antheridium of Marchantia, showing the numerous cells that develop the male gametes and the wall cells, w. E, greatly enlarged view of a male gamete after discharge from the antheridium. and in some species appear as lines radiating from the center of the plant. The male gametangium originates from one of the superficial cells of the thallus, which at first continues to divide • transversely after the manner of the vertical plates of chlorophyll- bearing cells (Fig. i8i, A). The cells of these vertical plates soon begin to divide vertically and thus form an elliptical mass of cells (Fig. i8i, 5, C). As this growth goes on the outer or wall cells become larger than the others and generally develop chlorophyll, while the inner cells divide repeatedly and become. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Curtis, Carlton Clarence, 1864-1945. New York, H. Holt
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