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Isoetes Nana
''Isoetes'', commonly known as the quillworts, is the only extant genus of plants in the family Isoetaceae, which is in the class of Lycopodiopsida, lycopods. There are currently 192 recognized species, with a cosmopolitan distribution but with the individual species often scarce to rare. Some botanists split the genus, separating two South American species into the genus ''Stylites'', although molecular data place these species among other species of ''Isoetes'', so that ''Stylites'' does not warrant taxonomic recognition. Species of ''Isoetes'' virtually identical to modern forms have existed since the Jurassic epoch. The name of the genus may also be spelled ''Isoëtes''. The Diaeresis (diacritic), diaeresis (two dots over the e) indicates that the o and the e are to be pronounced in two distinct syllables. Including this in print is optional; either spelling (''Isoetes'' or ''Isoëtes'') is correct. Description Quillworts are mostly aquatic or semi-aquatic in clear ponds and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoetes Tegetiformans
''Isoetes tegetiformans'', commonly known as mat-forming quillwort or mat-forming Merlin's grass, is an aquatic lycophyte endemic to the U.S. state of Georgia. It grows exclusively in shallow, temporary pools on granite outcrops, often with only 2 cm of soil. Only 7 populations are known to exist, and three of these have been destroyed since the plant's discovery in 1976. The remaining populations are threatened with habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ... due to quarrying, though the species is protected under the U.S. Endangered Species Act. New leaves quickly sprout after fall and winter rains, but during the dry summer months these typically shrivel. References External links Profile at USDA Plants Profile for ''Isoetes tegetiformans'' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizome
In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow horizontally. The rhizome also retains the ability to allow new shoots to grow upwards. A rhizome is the main stem of the plant that runs underground horizontally. A stolon is similar to a rhizome, but a stolon sprouts from an existing stem, has long internodes, and generates new shoots at the end, such as in the strawberry plant. In general, rhizomes have short internodes, send out roots from the bottom of the nodes, and generate new upward-growing shoots from the top of the nodes. A stem tuber is a thickened part of a rhizome or stolon that has been enlarged for use as a storage organ. In general, a tuber is high in starch, e.g. the potato, which is a modified stolon. The term "tuber" is often used imprecisely and is sometimes applied to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodiaceae
The Lycopodiaceae (class Lycopodiopsida, order Lycopodiales) are an old family of vascular plants, including all of the core clubmosses and firmosses, comprising 16 accepted genera and about 400 known species. This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. "Wolf foot" is another common name for this family due to the resemblance of either the roots or branch tips to a wolf's paw. Description Members of Lycopodiaceae are not spermatophytes and so do not produce seeds. Instead they produce spores, which are oily and flammable, and are the most economically important aspects of these plants. The spores are of one size (i.e. the plants are isosporous) and are borne on a specialized structure at the apex of a shoot called a strobilus (plural: strobili), which resembles a tiny battle club, from which the common name derives. Members of the family share the common feature of having a microphyll, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterospory
Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore, is male and the larger megaspore is female. Heterospory evolved during the Devonian period from isospory independently in several plant groups: the clubmosses, the ferns including the arborescent horsetails, and progymnosperms. This occurred as part of the process of evolution of the timing of sex differentiation.Sussex, I.M. (1966) The origin and development of heterospory in vascular plants. Chapter 9 in ''Trends in Plant morphogenesis'', ed. by E.G. Cutter, Longmans. Origin of heterospory Heterospory evolved due to natural selection that favoured an increase in propagule size compared with the smaller spores of homosporous plants. Heterosporous plants, similar to anisosporic plants, produce two different sized spores in separate sporangia that develop into separate male and female gametophytes. It is proposed that the emergence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selaginellaceae
''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae The Lycopodiaceae (class Lycopodiopsida, order Lycopodiales) are an old family of vascular plants, including all of the core clubmosses and firmosses, comprising 16 accepted genera and about 400 known species. This family originated about 380 mil ... (the clubmosses) by having scale-leaves bearing a ligule and by having heterospory, spores of two types. They are sometimes included in an informal paraphyletic group called the "fern ally, fern allies". ''Selaginella moellendorffii, S. moellendorffii'' is an important model organism. Its genome has been sequenced by the United States Department of Energy's Joint Genome Institute. The name ''Selaginella'' was erected by Palisot de Beauvois solely for the species ''Selaginella selaginoides'', which turns out (with the closely related ''Selaginella deflexa'') to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidodendron
''Lepidodendron'' is an extinct genus of primitive vascular plants belonging to the family Lepidodendraceae, part of a group of Lycopodiopsida known as scale trees or arborescent lycophytes, related to Isoetes, quillworts and Lycopodiopsida, lycopsids (club mosses). They were part of the coal forest flora. They sometimes reached heights of , and the trunks were often over in diameter. They thrived during the Carboniferous Period (358.9 to 298.9 million years ago). Sometimes erroneously called "giant club mosses", the genus was actually more closely related to modern quillworts than to modern club mosses. Within the form classification system used within paleobotany, ''Lepidodendron'' is both used for the whole plant as well as specifically the stems and leaves. Etymology The name ''Lepidodendron'' comes from the Greek language, Greek wikt:λεπίς, λεπίς ', scale, and wikt:δένδρον, δένδρον ''dendron'', tree. Growth During the early stages of growth, ''L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiosperms
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils are in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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