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Conifers typically bear their microsporangia on microsporophylls aggregated into papery pollen strobili, and the ovules, are located on modified stem axes forming compound ovuliferous cone scales. Flowering plants contain microsporangia in the anthers of stamens (typically four microsporangia per anther) and megasporangia inside ovules inside ...
Encephalartos villosus microsporophylls with microsporangia. A microsporangium (pl. microsporangia) is a sporangium that produces microspores that give rise to male gametophytes when they germinate. Microsporangia occur in all vascular plants that have heterosporic life cycles, such as seed plants, spike mosses and the aquatic fern genus Azolla.
An anther and its filament together form a typical (or filantherous) stamen, part of the male floral organ. The typical anther is bilocular, i.e. it consists of two thecae. Each theca contains two microsporangia, also known as pollen sacs. The microsporangia produce the microspores, which for seed plants are known as pollen grains.
The microsporangia of gymnosperms develop in pairs toward the bases of the scales, which are therefore called microsporophylls. Each of the microsporocytes in the microsporangia undergoes meiosis, producing four haploid microspores. These develop into pollen grains, each consisting of four cells and, in conifers, a pair of external air sacs.
Most famous parts of the brain highlighted in different colours The human brain anatomical regions are ordered following standard neuroanatomy hierarchies. Functional , connective , and developmental regions are listed in parentheses where appropriate.
In neuroanatomy, the paracentral lobule is on the medial surface of the cerebral hemisphere and is the continuation of the precentral and postcentral gyri.The paracentral lobule controls motor and sensory innervations of the contralateral lower extremity.
A link between these types of drugs and cognitive impairment isn't a totally new discovery, but for the first time, researchers used brain imaging techniques to determine the physical changes ...
Yellow softening is the third type of cerebral softening. As its name implies, the affected softened areas of the brain have a yellow appearance. This yellow appearance is due to atherosclerotic plaque build-up in interior brain arteries coupled with yellow lymph around the choroid plexus, which occurs in specific instances of brain trauma. [2]