Misplaced Pages

#744255

34-496: See text Hesperocyparis ( western cypress ) is a genus of trees in the family Cupressaceae , containing North American species otherwise assigned to the genus Cupressus . They are found throughout western North America . Only a few species have wide ranges, with most being restricted-range endemics . Members of Hesperocyparis were and still are placed in Cupressus by many authorities, but phylogenetic evidence supports

68-479: A grade basal to Cupressaceae sensu stricto , containing Callitroideae and Cupressoideae . The former Taxodiaceae genus, Sciadopitys , has been moved to a separate monotypic family Sciadopityaceae due to being genetically distinct from the rest of the Cupressaceae. In some classifications Cupressaceae is raised to an order, Cupressales. Molecular evidence supports Cupressaceae being the sister group to

102-763: A zygote . The definition avoids reference to male and female reproductive structures, which are rare in fungi. An individual of a dioecious fungal species not only requires a partner for mating, but performs only one of the roles in nuclear transfer, as either the donor or the recipient. A monoecious fungal species can perform both roles, but may not be self-compatible. Dioecy has the demographic disadvantage compared with hermaphroditism that only about half of reproductive adults are able to produce offspring. Dioecious species must therefore have fitness advantages to compensate for this cost through increased survival, growth, or reproduction. Dioecy excludes self-fertilization and promotes allogamy (outcrossing), and thus tends to reduce

136-592: A different affinity. A 2021 molecular study found Hesperocyparis to be the sister group to the genus Callitropsis (containing only the Nootka cypress ), with this clade being sister to the Asian genus Xanthocyparis , containing only the Vietnamese golden cypress . The clade comprising all three genera was found to be sister to a clade containing Juniperus and Cupressus sensu stricto . If Hesperocyparis and

170-436: A frequency about half of that for the forward transition. In Silene , since there is no monoecy, it is suggested that dioecy evolved through gynodioecy. Very few dioecious fungi have been discovered. Monoecy and dioecy in fungi refer to the donor and recipient roles in mating, where a nucleus is transferred from one haploid hypha to another, and the two nuclei then present in the same cell merge by karyogamy to form

204-422: A very similar phylogeny but with some slight differences, along with the splitting of Cupressus (found to be paraphyletic): Cunninghamia Taiwania Athrotaxis Metasequoia Sequoia Sequoiadendron Cryptomeria Glyptostrobus Taxodium Austrocedrus Papuacedrus Dioecious In zoology, dioecy means that an animal is either male or female, in which case

238-424: Is a stub . You can help Misplaced Pages by expanding it . Cupressaceae Cupressaceae or the cypress family is a family of conifers . The family includes 27–30 genera (17 monotypic ), which include the junipers and redwoods , with about 130–140 species in total. They are monoecious , subdioecious or (rarely) dioecious trees and shrubs up to 116 m (381 ft) tall. The bark of mature trees

272-788: Is called " dioecious " when each sporophyte plant has only one kind of spore-producing organ, all of whose spores give rise either to male gametophytes, which produce only male gametes (sperm), or to female gametophytes, which produce only female gametes (egg cells). For example, a single flowering plant sporophyte of a fully dioecious species like holly has either flowers with functional stamens producing pollen containing male gametes (staminate or 'male' flowers), or flowers with functional carpels producing female gametes (carpellate or 'female' flowers), but not both. (See Plant reproductive morphology for further details, including more complex cases, such as gynodioecy and androdioecy .) Slightly different terms, dioicous and monoicous , may be used for

306-407: Is commonly orange- to red-brown and of stringy texture, often flaking or peeling in vertical strips, but smooth, scaly or hard and square-cracked in some species. The family reached its peak of diversity during the mesozoic era. The leaves are arranged either spirally, in decussate pairs (opposite pairs, each pair at 90° to the previous pair) or in decussate whorls of three or four, depending on

340-459: Is more common in woody plants , and heterotrophic species. In most dioecious plants, whether male or female gametophytes are produced is determined genetically, but in some cases it can be determined by the environment, as in Arisaema species. Certain algae , such as some species of Polysiphonia , are dioecious. Dioecy is prevalent in the brown algae ( Phaeophyceae ) and may have been

374-406: Is unlikely that mutations for male and female sterility occurred at the same time. In angiosperms unisexual flowers evolve from bisexual ones. Dioecy occurs in almost half of plant families, but only in a minority of genera, suggesting recent evolution. For 160 families that have dioecious species, dioecy is thought to have evolved more than 100 times. In the family Caricaceae , dioecy is likely

SECTION 10

#1732790139745

408-648: The Cenomanian of North America, and they subsequently diversified during the Late Cretaceous and early Cenozoic. The family is divided into seven subfamilies, based on genetic and morphological analysis as follows: A 2010 study of Actinostrobus and Callitris places the three species of Actinostrobus within an expanded Callitris based on analysis of 42 morphological and anatomical characters. Phylogeny based on 2000 study of morphological and molecular data. Several further papers have suggested

442-435: The gametophyte generation of non-vascular plants, although dioecious and monoecious are also used. A dioicous gametophyte either produces only male gametes (sperm) or produces only female gametes (egg cells). About 60% of liverworts are dioicous. Dioecy occurs in a wide variety of plant groups. Examples of dioecious plant species include ginkgos , willows , cannabis and African teak . As its specific name implies,

476-439: The gametophytes , which produce gametes. A male gamete and a female gamete then fuse to produce a new diploid sporophyte. In bryophytes ( mosses , liverworts and hornworts ), the gametophytes are fully independent plants. Seed plant gametophytes are dependent on the sporophyte and develop within the spores, a condition known as endospory . In flowering plants, the male gametophytes develop within pollen grains produced by

510-487: The Cupressaceae, as do six of the ten longest-lived tree species . Molecular and morphological studies have expanded Cupressaceae to include the genera of Taxodiaceae , previously treated as a distinct family, but now shown not to differ from the Cupressaceae in any consistent characteristics. The member genera have been placed into five distinct subfamilies of Cupressaceae, Athrotaxidoideae , Cunninghamioideae , Sequoioideae , Taiwanioideae , and Taxodioideae , which form

544-458: The ancestral sexual system. Dioecious flowering plants can evolve from monoecious ancestors that have flowers containing both functional stamens and functional carpels. Some authors argue monoecy and dioecy are related. In the genus Sagittaria , since there is a distribution of sexual systems, it has been postulated that dioecy evolved from monoecy through gynodioecy mainly from mutations that resulted in male sterility. However, since

578-568: The ancestral state in that group. In plants, dioecy has evolved independently multiple times either from hermaphroditic species or from monoecious species. A previously untested hypothesis is that this reduces inbreeding; dioecy has been shown to be associated with increased genetic diversity and greater protection against deleterious mutations. Regardless of the evolutionary pathway the intermediate states need to have fitness advantages compared to cosexual flowers in order to survive. Dioecy evolves due to male or female sterility, although it

612-609: The ancestral state is unclear, more work is needed to clarify the evolution of dioecy via monoecy. Dioecy usually evolves from hermaphroditism through gynodioecy but may also evolve through androdioecy , through distyly or through heterostyly . In the Asteraceae , dioecy may have evolved independently from hermaphroditism at least 5 or 9 times. The reverse transition, from dioecy back to hermaphroditism has also been observed, both in Asteraceae and in bryophytes, with

646-464: The bark starts to flake. Most are evergreen with the leaves persisting 2–10 years, but three genera ( Glyptostrobus , Metasequoia and Taxodium ) are deciduous or include deciduous species. The seed cones are either woody, leathery, or (in Juniperus ) berry-like and fleshy, with one to several ovules per scale. The bract scale and ovuliferous scale are fused together except at the apex, where

680-456: The bract scale is often visible as a short spine (often called an umbo) on the ovuliferous scale. As with the foliage, the cone scales are arranged spirally, decussate (opposite) or whorled, depending on the genus. The seeds are mostly small and somewhat flattened, with two narrow wings, one down each side of the seed; rarely (e.g. Actinostrobus ) triangular in section with three wings; in some genera (e.g. Glyptostrobus and Libocedrus ), one of

714-595: The exceptions of polar tundra and tropical lowland rainforest (though several species are important components of temperate rainforests and tropical highland cloud forests ); they are also rare in deserts , with only a few species able to tolerate severe drought, notably Cupressus dupreziana in the central Sahara . Despite the wide overall distribution, many genera and species show very restricted relictual distributions, and many are endangered species . The world's largest ( Sequoiadendron giganteum ) and current tallest ( Sequoia sempervirens ) trees belong to

SECTION 20

#1732790139745

748-585: The expression of recessive deleterious mutations present in a population. In trees, compensation is realized mainly through increased seed production by females. This in turn is facilitated by a lower contribution of reproduction to population growth, which results in no demonstrable net costs of having males in the population compared to being hermaphroditic. Dioecy may also accelerate or retard lineage diversification in angiosperms . Dioecious lineages are more diversified in certain genera, but less in others. An analysis suggested that dioecy neither consistently places

782-402: The genus. On young plants, the leaves are needle-like, becoming small and scale-like on mature plants of many genera; some genera and species retain needle-like leaves throughout their lives. Old leaves are mostly not shed individually, but in small sprays of foliage ( cladoptosis ); exceptions are leaves on the shoots that develop into branches. These leaves eventually fall off individually when

816-700: The genus; they may be borne singly at the apex of a shoot (most genera), in the leaf axils ( Cryptomeria ), in dense clusters ( Cunninghamia and Juniperus drupacea ), or on discrete long pendulous panicle -like shoots ( Metasequoia and Taxodium ). Cupressaceae is a widely distributed conifer family, with a near-global range in all continents except for Antarctica, stretching from 70°N in arctic Norway ( Juniperus communis ) to 55°S in southernmost Chile ( Pilgerodendron uviferum ), further south than any other conifer species. Juniperus indica reaches 4930 m altitude in Tibet . Most habitats on land are occupied, with

850-476: The number of chromosomes of the individual producing them, so are haploid . Without further dividing, a sperm and an egg cell fuse to form a zygote that develops into a new individual. In land plants, by contrast, one generation – the sporophyte generation – consists of individuals that produce haploid spores rather than haploid gametes . Spores do not fuse, but germinate by dividing repeatedly by mitosis to give rise to haploid multicellular individuals,

884-564: The other smaller genera were reunited with Cupressus it may also require them to be merged into a larger genus including Juniperus . As of 2024 Hesperocyparis is listed as the correct classification by Plants of the World Online , World Flora Online , and the Gymnosperm Database. There is disagreement about this classification, with some scientists continuing to use Cupressus in preference to Hesperocyparis . At

918-657: The perennial stinging nettle Urtica dioica is dioecious, while the annual nettle Urtica urens is monoecious. Dioecious flora are predominant in tropical environments. About 65% of gymnosperm species are dioecious, but almost all conifers are monoecious. In gymnosperms, the sexual systems dioecy and monoecy are strongly correlated with the mode of pollen dispersal, monoecious species are predominantly wind dispersed ( anemophily ) and dioecious species animal-dispersed ( zoophily ). About 6 percent of flowering plant species are entirely dioecious and about 7% of angiosperm genera contain some dioecious species. Dioecy

952-644: The primitive living cypress genera Taiwania and Cunninghamia . By the Middle to Late Jurassic Cupressaceae were abundant in warm temperate–tropical regions of the Northern Hemisphere. The diversity of the group continued to increase during the Cretaceous period. The earliest appearance of the non-taxodiaceous Cupressaceae (the clade containing Callitroideae and Cupressoideae) is in the mid-Cretaceous, represented by " Widdringtonia" americana from

986-778: The segregation Cupressus species into four total genera. Cunninghamia Taiwania Athrotaxis Metasequoia Sequoia Sequoiadendron Cryptomeria Glyptostrobus Taxodium Austrocedrus Papuacedrus Libocedrus Pilgerodendron Widdringtonia Diselma Fitzroya Neocallitropsis Actinostrobus Callitris (sometimes including Actinostrobus and Neocallitropsis ) Thuja Thujopsis Chamaecyparis (sometimes including Fokienia ) Calocedrus Tetraclinis Microbiota Platycladus Cupressus (sometimes split into Callitropsis , Cupressus , Hesperocyparis , and Xanthocyparis ) Juniperus A 2021 molecular study supported

1020-1277: The species level there is also uncertainty as to the number of species. In part this is because the north west of Mexico has not been sufficiently surveyed to give enough information to definitively determine if a number of species there and in the southwestern United States are fully separate species or part of a species complex . Juniperus Cupressus s.s. Xanthocyparis vietnamensis Farjon & Nguyên Callitropsis nootkatensis (Don) Oersted H. bakeri (Jepson) Bartel (Modoc cypress) H. macnabiana (Murray) Bartel (Macnab’s/Shasta cypress) H. goveniana (Gordon) Bartel (Gowen cypress) H. macrocarpa (Hartweg ex Gordon) Bartel (Monterey cypress) H. sargentii Jepson (Sargent cypress) H. glabra (Sudworth) Bartel (Smooth Arizona cypress) H. arizonica (Greene) Bartel (Arizona cypress) H. guadalupensis (Watson) Bartel (Guadalupe cypress) H. montana (Wiggins) Bartel (San Pedro Martir cypress) H. forbesii (Jepson) Bartel (Tecate cypress) H. lusitanica (Miller) Bartel (Mexican cypress) H. stephensonii (Jepson) Bartel (Cuyamaca cypress) Additional species: New World Species : This conifer -related article

1054-460: The sporophyte's stamens , and the female gametophytes develop within ovules produced by the sporophyte's carpels . The sporophyte generation of a seed plant is called " monoecious " when each sporophyte plant has both kinds of spore-producing organ but in separate flowers or cones. For example, a single flowering plant of a monoecious species has both functional stamens and carpels, in separate flowers. The sporophyte generation of seed plants

Hesperocyparis - Misplaced Pages Continue

1088-594: The synonym gonochory is more often used. For example, most animal species are gonochoric, almost all vertebrate species are gonochoric, and all bird and mammal species are gonochoric. Dioecy may also describe colonies within a species, such as the colonies of Siphonophorae (Portuguese man-of-war), which may be either dioecious or monoecious . Land plants ( embryophytes ) differ from animals in that their life cycle involves alternation of generations . In animals, typically an individual produces gametes of one kind, either sperm or egg cells . The gametes have half

1122-415: The wings is significantly larger than the other, and in some others (e.g. Juniperus , Microbiota , Platycladus , and Taxodium ) the seed is larger and wingless. The seedlings usually have two cotyledons , but in some species up to six. The pollen cones are more uniform in structure across the family, 1–20 mm long, with the scales again arranged spirally, decussate (opposite) or whorled, depending on

1156-509: The yews (family Taxaceae ), from which it diverged during the early-mid Triassic . The clade comprising both is sister to Sciadopityaceae, which diverged from them during the early-mid Permian . The oldest definitive record of Cupressaceae is Austrohamia minuta from the Early Jurassic ( Pliensbachian ) of Patagonia, known from many parts of the plant. The reproductive structures of Austrohamia have strong similarities to those of

#744255