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Strasburgeriaceae
Strasburgeriaceae is a small family of flowering plants in the order Crossosomatales, only found in New Zealand and New Caledonia. It contains two genera, ''Strasburgeria'' and ''Ixerba''. Both genera have simple, evergreen, alternated leaves, often in worl-like clusters, with gland-tipped serrations, hermaphroditic, pentamerous flowers with persistent sepals, clawed petals, flat and long filaments that extend beyond the petals and a persistent style with a punctiform stigma. Fossil pollen named ''Bluffopollis scabratus'', found in deposits from the Paleocene to the Miocene, is almost identical to the pollen of ''Strasburgeria'', although only half its size. The fact that it was found in western and southern Australia and in New Zealand suggests that the most recent common ancestor of ''Strasburgeria'' and ''Ixerba'' had developed by the time of the break-up of East-Gondwana. Recent phylogenetic analysis resulted in the inclusion of the genus ''Ixerba'' (previously assigned to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strasburgeria Robusta
''Strasburgeria robusta'' is an evergreen tree with large toothed leaves and large but rather inconspicuous, single, pendulant flowers in a gloomy colorscheme of yellowish with brown markings, with about ten sepals, five petals, ten stamens, a very distinct circular nectar gland with radiating spikes and rather large globular fruits with a long persistent style, with a scent reminiscent of apples, which is endemic to New Caledonia. It is the only recognized species of the genus ''Strasburgeria''. Description ''Strasburgeria robusta'' is an icosaploid with five hundred chromosomes, in twenty sets of twenty five (20n = 500). This massive polyploidy in ''S. robusta'' may have enabled the adaptations that let it survive on the ultramafic substrates found in the montane forest of New Caledonia. Stems and leaves The wood of ''Strasburgeria'' does not have growth rings. Wood vessels are mostly isolated but sometimes occur in pairs or with three together. The ending of the vess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strasburgeria
''Strasburgeria robusta'' is an evergreen tree with large toothed leaves and large but rather inconspicuous, single, pendulant flowers in a gloomy colorscheme of yellowish with brown markings, with about ten sepals, five petals, ten stamens, a very distinct circular nectar gland with radiating spikes and rather large globular fruits with a long persistent style, with a scent reminiscent of apples, which is endemic to New Caledonia. It is the only recognized species of the genus ''Strasburgeria''. Description ''Strasburgeria robusta'' is an icosaploid with five hundred chromosomes, in twenty sets of twenty five (20n = 500). This massive polyploidy in ''S. robusta'' may have enabled the adaptations that let it survive on the ultramafic substrates found in the montane forest of New Caledonia. Stems and leaves The wood of ''Strasburgeria'' does not have growth rings. Wood vessels are mostly isolated but sometimes occur in pairs or with three together. The ending of the vess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ixerba
''Ixerba brexioides'', the sole species in the genus ''Ixerba'', is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green heart. The fruit is a green capsule that splits open to reveal the black seeds partly covered with a fleshy scarlet aril against the white inside of the fruit. ''Ixerba'' is an endemic of the northern half of the North Island of New Zealand. Common names used in New Zealand are tawari ( mi, tāwari) for the tree and whakou when in flower. It is assigned to the family Strasburgeriaceae. Description Stem and leaves Tawari is a small tree of up to 10 m high with a spreading crown. The trunk is usually between 2–4 dm in diameter, and covered by a dark to grayish brown bark. Young branches have few flat-lying pale unicellular T-hairs, while the peduncles, pedicels, sepals and petals are thickly covered in such hairs, giving them a felty look. The leaves are alternately positioned along the stem and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ixerba Brexioides
''Ixerba brexioides'', the sole species in the genus ''Ixerba'', is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green heart. The fruit is a green capsule that splits open to reveal the black seeds partly covered with a fleshy scarlet aril against the white inside of the fruit. ''Ixerba'' is an endemic of the northern half of the North Island of New Zealand. Common names used in New Zealand are tawari ( mi, tāwari) for the tree and whakou when in flower. It is assigned to the family Strasburgeriaceae. Description Stem and leaves Tawari is a small tree of up to 10 m high with a spreading crown. The trunk is usually between 2–4 dm in diameter, and covered by a dark to grayish brown bark. Young branches have few flat-lying pale unicellular T-hairs, while the peduncles, pedicels, sepals and petals are thickly covered in such hairs, giving them a felty look. The leaves are alternately positioned along the stem and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossosomatales
The Crossosomatales are an order, first recognized as such by APG II. They are flowering plants included within the Rosid eudicots. Description Species assigned to the Crossosomatales have in common flowers that are positioned solitarily, with the base of the calyx, corolla, and stamens fused into a tube-shaped floral cup, sepals overlapping, the outermost smaller than the inner. Insides of the casings of pollen grains have horizontally extended thin regions (or endo-apertures). The gynoecium is placed on a short stalk, papillae on the stigma consist of two or more cells, ovary locules taper upwards, and the protective cell layer (or integument) surrounding the ovule leaves a zigzag opening (or micropyle). Some cell clusters have bundles of long yellow crystals, mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geissolomataceae
''Geissoloma'' is a genus of flowering plants in the monotypic family Geissolomataceae, native to the Cape Province of South Africa. The plants are xerophytic evergreen shrubs and are known to accumulate aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has .... It is sometimes called guyalone in English. Description ''Geissoloma marginatum'' is a low evergreen shrub of ½-1¼ m high, covered in overlapping large, leathery, simple, scale-like, opposite leaves in four rows along the stems. It has very small stipules on the petioles. Flowers are bisexual, subtended by bracts, and have four red to pinkish petaloid sepals, four petals partially united, eight stamens, and four carpels. The fruit is a capsule with four seeds. ''Geissoloma marginatum'' is the only species in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphloiaceae
''Aphloia'' is a genus of flowering plants that contains a single species, ''Aphloia theiformis'', the sole species of the monogeneric family Aphloiaceae. It is a species of evergreen shrubs or small trees occurring in East Africa, Madagascar, the Mascarene Islands and the Seychelles. Taxonomy The genus ''Aphloia'' was described by John Joseph Bennett in 1840 and included in Flacourtiaceae, where most authors continued to include it until Armen Takhtajan recognized its misplacement and created the new family Aphloiaceae in Violales to accommodate it. In 2003 the APG II system included Aphloiaceae in the Rosids without specifying an order. Matthews & Endress (2005) and Stevens (2006) include the family in an enlarged order Crossosomatales. The APG III system of 2009 followed suit and includes Aphloiaceae within the Crossosomatales. Description ''Aphloia theiformis'' is an evergreen shrub or small tree reaching up to high. Young branches are hairless, brown in colour, hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montane Forest
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial factor in shaping plant community, biodiversity, metabolic processes and ecosystem dynamics for montane ecosystems. Dense montane forests are common at moderate elevations, due to moderate temperatures and high rainfall. At higher elevations, the climate is harsher, with lower temperatures and higher winds, preventing the growth of trees and causing the plant community to transition to montane grasslands, shrublands or alpine tundra. Due to the unique climate conditions of montane ecosystems, they contain increased numbers of endemic species. Montane ecosystems also exhibit variation in ecosystem services, which include carbon storage and water supply. Life zones As elevation increases, the climate becomes cooler, due to a decrease in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultramafic Rock
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. Intrusive ultramafic rocks Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types do not represent the chemistry of the magma from which they crystallized. The ultramafic intrusives include the dunites, peridotites and pyroxenites. Other rare varieties include troctolite which has a greater percentag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyploid
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spores by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ploidy
Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair, which chromosomes naturally exist as. Somatic cells, Tissue (biology), tissues, and Individual#Biology, individual organisms can be described according to the number of sets of chromosomes present (the "ploidy level"): monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid or septaploid (7 sets), etc. The generic term polyploidy, polyploid is often used to describe cells with three or more chromosome sets. Virtually all sexual reproduction, sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossosomataceae
Crossosomataceae is a small plant family, consisting of four genera of shrubs found only in the dry parts of the American southwest and Mexico. This family has included up to ten species in the past, although as of 2021 six species are still recognised. ''Crossosoma'' are shrub-like plants which can vary from being 50 cm to 5 meters tall, with small alternating leaves that surround the stem, or leaves clustered in small spurts (fascicles).Richardson, P. (1970). Morphology of the Crossosomataceae. I. Leaf, Stem and Node. Bulletin of the Torrey Botanical Club, 97(1), 34-39. doi:10.2307/2483988 ''Apacheria'', however, has opposite leaves. ''Crossosoma'' has usually white flowers that are generally bisexual and have 5 petals attached to a nectary disk, but in ''Velascoa'' the flowers are campanulate and have an extremely reduced nectary disk. Genera *''Apacheria'' - one species, cliff brittlebush, '' Apacheria chiricahuensis'' *'' Crossosoma'' - two species, ''C. bigelovii' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
