. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. 2l8 REPRODUCTION is anchored to the soil by hair-hke rhizoids, and bears on its under side two sorts of sacs, one the antheridium (Fig. 125, A), containing sperm cells or male gametes, and the other the arche- gonium, B, bearing an egg cell or female gamete. Some pro- thallia, however, bear antheridia only. Since the prothallium bears the gametes we call it the gameto- phyte. Fertilization of the Egg.—The sperm cells swim by means of their cilia to the archegonia,
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. 2l8 REPRODUCTION is anchored to the soil by hair-hke rhizoids, and bears on its under side two sorts of sacs, one the antheridium (Fig. 125, A), containing sperm cells or male gametes, and the other the arche- gonium, B, bearing an egg cell or female gamete. Some pro- thallia, however, bear antheridia only. Since the prothallium bears the gametes we call it the gameto- phyte. Fertilization of the Egg.—The sperm cells swim by means of their cilia to the archegonia, through the water that gathers under the prothallia (Fig. 125, B), being attracted by a substance,. Fig. 125.—A, Antheridium containing sperm cells; B, archegonium containing an egg cell which has been found by five sperm cells. All from Osmunda cinnamomea. (After Campbell.) probably malic acid, diffusing through the water from its place of secretion in the archegonium. The sperm cell now fuses with the egg. Following this the fertilized egg cell begins a series of nuclear and cell-divisions leading up to the full-grown fern (Fig. 124, E); and this produces sporangia and spores essen- tially as already described for Aneimia. Because of its bearing spores the fern plant is called the sporophyte. Interpretation of Processes of Nuclear Division.—The interpretation that is now being put on the behavior of the nuclear substance during division as previously outlined is suggested not only by what we see under the microscope but also by what we observe in carrying on pedigree cultures of hybrids, as will soon appear. We can best lead up to the interpretation by. 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 Stevens, William Chase, 1861-. Philadelphia, P. Blakiston's Son
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantanatomy, bookyea
