A sporangium (from Late Latin , from Ancient Greek σπορά ( sporá ) 'seed' and ἀγγεῖον ( angeîon ) 'vessel'); pl. : sporangia ) 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 groups form sporangia at some point in their life cycle . Sporangia can produce spores by mitosis , but in land plants and many fungi, sporangia produce genetically distinct haploid spores by meiosis .
15-485: See text . Hamatophyton is a genus of the extinct Sphenophyllales horsetails. Unique to this genus among other Sphenophyllales is its lack of secondary xylem around the tips of the primary xylem arms. One of its species has also been placed in the genus Sphenophyllostachys , which is regarded as a synonym of Bowmanites by the Interim Register of Marine and Nonmarine Genera . The taxonomic status of
30-490: A portion of the understory in Carboniferous forests. The stem anatomy is protostelic ( root -like), containing a solid primary xylem core with secondary xylem tissue present in some species. The leaves, which can be several centimeters long, are borne on each node in whorls (called verticels) and are wedge-shaped, fan-shaped, linear, or forked. Reproductive parts are either long terminal cones (consisting of two lobes,
45-808: A single sporangium, which may be quite complex morphologically. Most non-vascular plants, as well as many lycophytes and most ferns, are homosporous (only one kind of spore is produced). Some lycophytes, such as the Selaginellaceae and Isoetaceae , the extinct Lepidodendrales , and ferns, such as the Marsileaceae and Salviniaceae are heterosporous (two kinds of spores are produced). These plants produce both microspores and megaspores , which give rise to gametophytes that are functionally male or female, respectively. Most heterosporous plants there are two kinds of sporangia, termed microsporangia and megasporangia. Sporangia can be terminal (on
60-863: A sister group to the present-day Equisetales ( horsetails ). They are fossils dating from the Devonian to the Triassic . They were common during the Late Pennsylvanian to Early Permian , with most of the fossils coming from the Carboniferous period. Sphenophyllales are small, slender branching plants, usually growing to a height of less than 1 m (3.3 ft) tall. The long stems range from 0.5 cm (0.20 in) to 1.2 cm (0.47 in) in diameter. The stems are jointed and ribbed with weak habits , making it probable that these plants were vine or shrub-like when alive, and formed
75-574: A sterile lower lobe and the fertile upper lobe bearing the sporangia ) or loose strobili . All sphenophylls are homosporous , with monolete or trilete spores . Sphenophyllales was first described by the British botanist and geologist Albert Seward in 1898. The name comes from the Greek words σφήν ("wedge") and φύλλον ("leaf"). Sphenophyllalean taxonomy is often derived from isolated fossilized parts of plants and classification may be based on
90-416: Is a stub . You can help Misplaced Pages by expanding it . Sphenophyllales † Hamatophyton † Bowmanites † Cheirostrobus † Columnisporites † Gondwanophyton † Lilpopia † Peltastrobus † Rinistachya † Rotafolia † Sentistrobus † Sphenophyllostachys † Sphenophyllum † Xihuphyllum Sphenophyllales is an extinct order of articulate land plants and
105-687: The adaxial surface (the upper side) of leaves or laterally on stems. Leaves that bear sporangia are called sporophylls . If the plant is heterosporous, the sporangia-bearing leaves are distinguished as either microsporophylls or megasporophylls. In seed plants, sporangia are typically located within strobili or flowers. Cycads form their microsporangia on microsporophylls which are aggregated into strobili. Megasporangia are formed into ovules, which are borne on megasporophylls, which are aggregated into strobili on separate plants (all cycads are dioecious). Conifers typically bear their microsporangia on microsporophylls aggregated into papery pollen strobili, and
120-742: The morphology and anatomy of sterile plant parts (like leaves ) or fructifications (mainly the fossilized cones and the stratigraphically -important spores found near them). This results in species that may actually by synonymous . Sphenophyllales is typified by the genus Sphenophyllum . The probable relationships within Equisetidae are shown in the cladogram below. The possible position of Ibyka has been added. † Ibyka (?) † Pseudobornia ursina †Sphenophyllales † Archaeocalamitaceae † Calamitaceae Equisetaceae [REDACTED] Media related to Sphenophyllales at Wikimedia Commons Sporangia In some phyla of fungi,
135-479: The basionym was invalid, this name is also invalid. Both species that have been placed in Hamatophyton are also treated as synonymous with Rotafolia songziensis . This fern -related article is a stub . You can help Misplaced Pages by expanding it . This article related to a Devonian plant is a stub . You can help Misplaced Pages by expanding it . This article related to a Carboniferous plant
150-550: The genus and its possible species is confused. As of February 2024, the International Fossil Plant Names Index regards Hamatophyton as an invalid name since its publication in 1974 because the species name on which the genus was based, Hamatophyton verticillatum , is invalid as no type was designated. In 1991, Hamatophyton verticillatum was transferred to the genus Sphenophyllostachys as Sphenophyllostachys verticillata , but since
165-577: 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 ovaries. In all seed plants, spores are produced by meiosis and develop into gametophytes while still inside the sporangium. The microspores become microgametophytes (pollen). The megaspores become megagametophytes (embryo sacs). Categorized based on developmental sequence, eusporangia and leptosporangia are differentiated in
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#1732793984641180-504: The sporangium plays a role in asexual reproduction , and may play an indirect role in sexual reproduction . The sporangium forms on the sporangiophore and contains haploid nuclei and cytoplasm . Spores are formed in the sporangiophore by encasing each haploid nucleus and cytoplasm in a tough outer membrane . During asexual reproduction, these spores are dispersed via wind and germinate into haploid hyphae . Although sexual reproduction in fungi varies between phyla, for some fungi
195-500: The sporangium plays an indirect role in sexual reproduction. For Zygomycota , sexual reproduction occurs when the haploid hyphae from two individuals join to form a zygosporangium in response to unfavorable conditions. The haploid nuclei within the zygosporangium then fuse into diploid nuclei. When conditions improve, the zygosporangium germinates, undergoes meiosis and produces a sporangium, which releases spores. In mosses, liverworts and hornworts, an unbranched sporophyte produces
210-452: 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 called sori . Sori may be covered by a structure called an indusium. Some ferns have their sporangia scattered along reduced leaf segments or along (or just in from) the margin of the leaf. Lycophytes, in contrast, bear their sporangia on
225-562: The vascular plants. A cluster of sporangia that have become fused in development is called a synangium (pl. synangia ). This structure is most prominent in Psilotum and Marattiaceae such as Christensenia , Danaea and Marattia . A columella (pl. columellae) is a sterile (non-reproductive) structure that extends into and supports the sporangium of some species. In fungi, the columella, which may be branched or unbranched, may be of fungal or host origin. Secotium species have
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