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A strobilus (pl.: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem.Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers.
However, unlike these other groups, ovules are produced on cone scales, which are modified shoots rather than sporophylls. Some plants do not produce sporophylls. Sporangia are produced directly on stems. Psilotum has been interpreted as producing sporangia (fused in a synangium) on the terminus of a stem.
Dehiscence of the follicular fruit of milkweed (Asclepias syriaca) revealing seeds within. Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part.
Sporangia (clustered in sori) on a fern leaf Equisetum arvense strobilus cut open to reveal sporangia. Sporangia can be terminal (on the tips) or lateral (placed along the side) of stems or associated with leaves. In ferns, sporangia are typically found on the abaxial surface (underside) of the leaf and are densely aggregated into clusters ...
A sorus (pl.: sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus ( pl. : coenosori ) is a compound sorus composed of multiple, fused sori. Etymology
The fertile shoots bear stout, yellowish cones which are only slightly differentiated from the branch. The cones usually bear two kinds of sporangia: lobed megasporangia in the lower part of the cone which produce megaspores and simple microsporangia in the upper part which produce many tiny microspores.
In angiosperms, the sporangia are located in the stamen anthers (microsporangia) and ovules (megasporangia). The specialised sporangia bearing stem is the flower . In angiosperms, if the female sporangium is fertilised , it becomes the fruit , a mechanism for dispersing the seeds produced from the embryo.
Sporangia are multispored, spherical, initially white to yellow, pale brown to dark brown at maturity and measure 40-160 μm. Sporangiospores from sporangia are ellipsoid to broadly ellipsoid, brown to dark brown, indistinctly striate with fine hyaline polar appendages, and measure 16-20 μm x 8-12 μm (Saroj et al. 2012).