Sporophyll

Last updated
The sporophyll of a fern. It is a fertile leaf bearing reproductive structures. Fern-frond-sori.jpg
The sporophyll of a fern. It is a fertile leaf bearing reproductive structures.

A sporophyll is a leaf that bears sporangia. 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 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. [1]

Lycophytes, 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.

Ferns, 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 .

Cycads produce strobili, both pollen-producing and seed-producing, that are composed of sporophylls.

Ginkgo produces microsporophylls aggregated into a pollen strobilus. Ovules are not born on sporophylls [ citation needed ].

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 always produce strobili, but the structures bearing sporangia (sporangiophores) have been interpreted as modified stems. The sporangia, despite being recurved are interpreted as terminal.

Gnetophytes produce both compound pollen and seed strobili.

Related Research Articles

<span class="mw-page-title-main">Sporangium</span> Enclosure in which spores are formed

A sporangium, also known as a "sporange", 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 cycle. Sporangia can produce spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis and produce genetically distinct haploid spores.

<span class="mw-page-title-main">Lycopodiopsida</span> Class of vascular plants

Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms (Lepidodendrales) formed huge forests that dominated the landscape and contributed to coal deposits.

<span class="mw-page-title-main">Cycad</span> Division of naked seeded dioecious plants

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 or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.

<span class="mw-page-title-main">Gymnosperm</span> Clade of non-flowering, naked-seeded vascular plants

The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: γυμνόσπερμος, literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, Ginkgo. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used.

<span class="mw-page-title-main">Sporophyte</span> Diploid multicellular stage in the life cycle of a plant or alga

A sporophyte is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase.

<span class="mw-page-title-main">Frond</span> Collection of leaflets on a plant

A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the large leaves of cycads, as well as palms (Arecaceae) and various other flowering plants, such as mimosa or sumac. "Frond" is commonly used to identify a large, compound leaf, but if the term is used botanically to refer to the leaves of ferns and algae it may be applied to smaller and undivided leaves.

<i>Stangeria</i> Monotypic genus of cycads in the family Stangeriaceae

Stangeria eriopus is a cycad endemic to southern Africa. It is the sole species in the genus Stangeria, most closely related to the Australian genus Bowenia, with which it forms the family Stangeriaceae.

<span class="mw-page-title-main">Equisetidae</span> Subclass of ferns

Equisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-like branches radiating at regular intervals from a single vertical stem.

<span class="mw-page-title-main">Zamiaceae</span> Family of cycads

The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of Africa, Australia and North and South America.

<span class="mw-page-title-main">Bennettitales</span> Extinct order of seed plants

Bennettitales is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales were amongst the most common seed plants of the Mesozoic, and had morphologies including shrub and cycad-like forms. The foliage of bennettitaleans is superficially nearly indistinguishable from that of cycads, but they are distinguished from cycads by their more complex flower-like reproductive organs, at least some of which were likely pollinated by insects.

<i>Dioon</i> Genus of cycads in the family Zamiaceae

Dioon is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes.

<span class="mw-page-title-main">Microspore</span> Small land plant spores that develop into male gametophytes

Microspores are land plant spores that develop into male gametophytes, whereas megaspores develop into female gametophytes. The male gametophyte gives rise to sperm cells, which are used for fertilization of an egg cell to form a zygote. Megaspores are structures that are part of the alternation of generations in many seedless vascular cryptogams, all gymnosperms and all angiosperms. Plants with heterosporous life cycles using microspores and megaspores arose independently in several plant groups during the Devonian period. Microspores are haploid, and are produced from diploid microsporocytes by meiosis.

A strobilus 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. Strobili are characterized by a central axis surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems.

In botany, a zoid or zoïd is a reproductive cell that possesses one or more flagella, and is capable of independent movement. Zoid can refer to either an asexually reproductive spore or a sexually reproductive gamete. In sexually reproductive gametes, zoids can be either male or female depending on the species. For example, some brown alga (Phaeophyceae) reproduce by producing multi-flagellated male and female gametes that recombine to form the diploid sporangia. Zoids are primarily found in some protists, diatoms, green alga, brown alga, non-vascular plants, and a few vascular plants. The most common classification group that produces zoids is the heterokonts or stramenopiles. These include green alga, brown alga, oomycetes, and some protists. The term is generally not used to describe motile, flagellated sperm found in animals. Zoid is also commonly confused for zooid which is a single organism that is part of a colonial animal.

This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.

<i>Macrozamia concinna</i> Species of cycad

Macrozamia concinna is a part of the plant family, Zamiaceae. It originates from a division of Cycadophyta which encompasses the complete species of cycads. M. concinna is primarily habituated in New South Wales, Australia and maintains a distinct appearance allowing it to be easily identifiable from other cycads. M. concinna also implements a unique method of reproduction to fertilise its offsprings, as opposed to the common method of wind pollination. This difference in reproduction mechanisms has survived throughout the ages of prehistoric cycad species and M. concinna continues to procreate with it.

<i>Phlegmariurus phlegmaria</i> Species of fern

Phlegmariurus phlegmaria, synonym Huperzia phlegmaria, commonly known as either coarse tassel fern or common tassel fern, is an epiphytic species native to rainforests in Madagascar, some islands in the Indian Ocean, Asia, Australasia and many Pacific Islands. Phlegmariurus phlegmaria is commonly found in moist forests and rainforests at high altitudes, in and amongst mosses and other epiphytes. Members of the order Lycopodiales are commonly referred to as clubmosses.

This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.

<span class="mw-page-title-main">Medullosales</span> Extinct order of Late Carboniferous seed ferns

The Medullosales is an extinct order of pteridospermous seed plants characterised by large ovules with circular cross-section and a vascularised nucellus, complex pollen-organs, stems and rachides with a dissected stele, and frond-like leaves. Their nearest still-living relatives are the cycads.

<span class="mw-page-title-main">Lyginopteridales</span> Prehistoric plant order

The Lyginopteridales are an extinct group of seed plants known from the Paleozoic. They were the first plant fossils to be described as pteridosperms and, thus, the group on which the concept of pteridosperms was first developed; they are the stratigraphically oldest-known pteridosperms, occurring first in late Devonian strata; and they have the most primitive features, most notably in the structure of their ovules. They probably evolved from a group of Late Devonian progymnosperms known as the Aneurophytales, which had large, compound frond-like leaves. The Lyginopteridales became the most abundant group of pteridosperms during Mississippian times, and included both trees and smaller plants. During early and most of middle Pennsylvanian times the Medullosales took over as the more important of the larger pteridosperms but the Lyginopteridales continued to flourish as climbing (lianescent) and scrambling plants. However, later in Middle Pennsylvanian times the Lyginopteridales went into serious decline, probably being out-competed by the Callistophytales that occupied similar ecological niches but had more sophisticated reproductive strategies. A few species continued into Late Pennsylvanian times, and in Cathaysia and east equatorial Gondwana they persisted into the Late Permian, but subsequently became extinct. Most evidence of the Lyginopteridales suggests that they grew in tropical latitudes of the time, in North America, Europe and China.

References

  1. Dickson, Carola I. 1963. British Seaweeds. The Kew Series.