एक संयंत्र संरचना जो micropores पैदा करता है

microsporangia's Usage Examples:

in the cone attributed to the Lower Carboniferous Lepidodendron Veltheimianum) the arrangement was that usual in Selaginella, the microsporangia occurring above and the megasporangia below in the same strobilus (diagram, fig.

It is very doubtful whether any homosporous Lepidostrobi existed, but there is reason to believe that here, as in the closely allied Lepidocarpon, microsporangia and megasporangia were in some cases borne on different strobili.

The pollen-grains or microspores contained in the anther consist of small cells, which are developed in the large thick-walled mother-cells formed in the interior of the pollen-sacs (microsporangia) of the young anther.

These are with few exceptions foliar structures, known in comparative morphology as sporophylls, because they bear the spores, namely, the microspores or pollen-grains which are developed in the microsporangia or pollen-sacs, and the megaspore, which is contained in the ovule or megasporangium.

Each sorus includes both microsporangia, with numerous spores, and megasporangia, each of which contains a single megaspore with a complicated wall.

They consist either of microsporangia or megasporangia, which are arranged in basipetal succession on the receptacle.

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.

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.

(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 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.

microsporangia's Meaning':

a plant structure that produces microspores