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. Botany; principles and problems. Botany. THE SPERM A TOI'IIYTA 353 As its name implies, the reproductive structures in this order are typically produced in cones. The microsporangial (staminate or "male") cones (Fig. 223) are short-lived and somewhat delicate structures, and each cone-scale (stamen or microsporo- phyll) bears two (rarely more) microsporangia on its lower or dorsal surface, in which the microspores or pollen grains are. Fig. 224.—Ovulate or "female" cones of the pine. developed (Fig. 218). The pollen is in all cases transferred to the ovules by wind. Excep

. Botany; principles and problems. Botany. THE SPERM A TOI'IIYTA 353 As its name implies, the reproductive structures in this order are typically produced in cones. The microsporangial (staminate or "male") cones (Fig. 223) are short-lived and somewhat delicate structures, and each cone-scale (stamen or microsporo- phyll) bears two (rarely more) microsporangia on its lower or dorsal surface, in which the microspores or pollen grains are. Fig. 224.—Ovulate or "female" cones of the pine. developed (Fig. 218). The pollen is in all cases transferred to the ovules by wind. Excep Stock Photo
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. Botany; principles and problems. Botany. THE SPERM A TOI'IIYTA 353 As its name implies, the reproductive structures in this order are typically produced in cones. The microsporangial (staminate or "male") cones (Fig. 223) are short-lived and somewhat delicate structures, and each cone-scale (stamen or microsporo- phyll) bears two (rarely more) microsporangia on its lower or dorsal surface, in which the microspores or pollen grains are. Fig. 224.—Ovulate or "female" cones of the pine. developed (Fig. 218). The pollen is in all cases transferred to the ovules by wind. Except for the rather small group Taxaceae, in which cone-scales or integuments become fleshy at maturity, the megasporangial (ovulate or "female") cones (Figs. 224 and 225) usually become hard and woody. Each cone-scale bears one or two ovules. In most cases the embryo-sac is distinctly smaller than that of the cycads and contains fewer cells (Fig. 217). The pollen alights on the nucellus and there germinates (Fig. 218). The generative cell at this time divides into two, a stalk cell and a body cell, which are believed to represent the remains of an antheridium. The body-cell in time follows the tube-nucleus down the pollen tube and divides into two male cells, one of which effects fertilization (Fig. 226). No pollen-chamber is formed, but the pollen-tube conveys the male cells, which are non-motile.. 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 work.. Sinnott, Edmund Ware, 1888-. New York, McGraw-Hill

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