Sporophyll
   HOME

TheInfoList



OR:

A sporophyll is a
leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...
that bears
sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...
. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls, or
microsporangia Microsporangia are sporangia that produce 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 fe ...
and are called microsporophylls. The overlap of the prefixes and roots makes these terms a particularly confusing subset of botanical nomenclature. Sporophylls vary greatly in appearance and structure, and may or may not look similar to sterile leaves. Plants that produce sporophylls include: '' Alaria esculenta'', a brown alga which shows sporophylls attached near the base of the alga.Dickson, Carola I. 1963. ''British Seaweeds''. The Kew Series.
Lycophyte The lycophytes, when broadly circumscribed, are a vascular plant (tracheophyte) subgroup of the kingdom Plantae. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldes ...
s, where sporophylls may be aggregated into strobili (''Selaginella'' and some ''Lycopodium'' and related genera) or distributed singly among sterile leaves ('' Huperzia''). Sporangia are borne in the axil or on the adaxial surface of the sporophyll. In heterosporous members, megasporophylls and microsporophylls may be intermixed or separated in a variety of patterns.
Fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...
s, which may produce sporophylls that are similar to sterile fronds or that appear very different from sterile fronds. These may be non-photosynthetic and lack typical pinnae, e.g. ''
Onoclea sensibilis ''Onoclea sensibilis'', the sensitive fern, also known as the bead fern, is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from its sensitivity to frost, the fronds dying quickly when first touched by it. It is ...
''.
Cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male o ...
s produce strobili, both pollen-producing and seed-producing, that are composed of sporophylls. ''
Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus with ...
'' produces microsporophylls aggregated into a pollen strobilus. Ovules are not born on sporophylls . Gymnosperms, like ''Ginkgo'' and cycads, produce microsporophylls, aggregated into pollen strobili. 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. ''
Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns, which reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass ...
'' always produce strobili, but the structures bearing sporangia (sporangiophores) have been interpreted as modified stems. The sporangia, despite being recurved are interpreted as terminal.
Gnetophyte Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three re ...
s produce both compound pollen and seed strobili.


References

* C.Michael Hogan. 2010
''Fern''. Encyclopedia of Earth. National council for Science and the Environment
Washington, DC Plant morphology Plant reproduction Plant anatomy {{Reflist