. Botany of the living plant. Botany; Plants. 5i8 BOTANY OF THE LIVING PLANT vestigial vegetative region, and a single antheridium. In certain cases starved Fern prothalli may be found of almost equal sim- plicity. A mucilaginous change appears in the walls of the central mass of cells. Meanwhile their protoplasts form each a single curved spermatozoid, motile in water by two cilia. Swelling of the mucilage by water bursts the wall of the spore, and the spermatozoids escape (Fig. 411, B). *US I .^^ ar ..71 â *-. Fig. 412. Embryology of Selagxnella denticulata, after Bruchmann. ( x iai)
. Botany of the living plant. Botany; Plants. 5i8 BOTANY OF THE LIVING PLANT vestigial vegetative region, and a single antheridium. In certain cases starved Fern prothalli may be found of almost equal sim- plicity. A mucilaginous change appears in the walls of the central mass of cells. Meanwhile their protoplasts form each a single curved spermatozoid, motile in water by two cilia. Swelling of the mucilage by water bursts the wall of the spore, and the spermatozoids escape (Fig. 411, B). *US I .^^ ar ..71 â *-. Fig. 412. Embryology of Selagxnella denticulata, after Bruchmann. ( x iai) show germination of megaspore. IV. vertical section of megaspore showing prothallus, archegonia, and embryo {em) with suspensor {sus) ( x 50). V. = a mature archegonium. of developing embryo. of S. cuspidata, after Belajeff. ( x 250.) The germination of the megaspores produces an internal tissue of greater extent, which may be styled the female prothallus. Its development begins below the meeting of the three converging ridges of the tetrahedral spore, and it extends into the spore-cavity, which is stored with nutritive material (Fig. 408). The increase in bulk of the contents ruptures the wall of the spore along the three converging ridges, so that the surface of the tissue is exposed (Fig. 412,1.). Near the central point the first archegonium appears, while laterally others may be formed later, but not in regular succession. A vertical section through a megaspore of 5. denticulata shows it completely filled with tissue of the prothallus, while its exposed surface bears rhizoids (rh) and archegonia in various stages of development (ar) (IV.). The. 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 Bower, F. O. (Frederick Orpen), 1855-1948; Wardlaw, C. W. (Claude Wilson), 1901-
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Keywords: ., bookcentury1900, bookpublis, booksubjectbotany, booksubjectplants
