Sentence Examples


  • The spores, as in the heterosporous Pteridophyta, are of two kindsmicrospores (pollen grains) borne in microsporangia (pollen sacs) on special leaves (sporophylls) known as stamens, and macrospores (embryo-sac) borne in macrosporangia (ovules) on sporophylls known as carpels.
  • (For further details on the form and arrangement of the flower and its parts, see Flower.) Each stamen generally bears four pollen-sacs (microsporangia) which are associated to form the anther, and carried up on a stalk or filament.
  • The development of the microsporangia and the contained spores (pollen -grains) P (P g is closely comparable with that of the microsporangia in Gymnosperms or heterosporous ferns.
  • A typical male flower consists of a central axis bearing numerous spirally-arranged sporophylls (stamens), each of which consists of a slender stalk (filament) terminating distally in a more or less prominent knob or triangular scale, and bearing two or more pollen-sacs (microsporangia) on its lower surface.
  • Each sorus includes both microsporangia, with numerous spores, and megasporangia, each of which contains a single megaspore with a complicated wall.
 

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