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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.
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
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 ...
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.
The cones could grow to be considerably large, as in Lepidostrobus goldernbergii specimens are over 50 cm (20 in) long. The cones consist of a central axis with sporophylls arranged helically; sporangia are on the adaxial surface of the sporophylls and are upturned distally to overlap sporophylls above. Part of the sporophyll typically extends ...
Horsetails bear cones (technically strobili, sing. strobilus ) at the tips of some stems. These cones comprise spirally arranged sporangiophores , which bear sporangia at their edges, and in extant horsetails cover the spores externally - like sacs hanging from an umbrella, with its handle embedded in the axis of the cone.
It primarily reproduces by vegetative means, with the majority of shoots arising from rhizomes. Spores are produced in sporangia in blunt-tipped cones at the tips of some stems. [2] [3] The spore cones are yellowish-green, 2,5 cm long. [3]