Pediocactus sileri ist eine Pflanzenart der Gattung Pediocactus in der Familie der Kakteengewächse (Cactaceae). Das Artepitheton der Art A. L. Siler, der die ersten Pflanzen entdeckte. Englische Trivialnamen sind „Gypsum Cactus“ und „Siler´s Pincushion Cactus“.
Die Art ist bedroht und wurde in den Anhang I des Washingtoner Artenschutzabkommens zum Schutz gefährdeter Arten aufgenommen.
Der grau bis blaugrüne, meist einzelne, manchmal gruppenbildende Pflanzenkörper ist kugelig bis eiförmig und wird im Alter zylindrisch. Er erreicht Wuchshöhen von 5 bis 20 cm (selten 30 cm) und Durchmesser von 5 bis 12 cm. Auf den konischen Warzen befinden sich runde bis ovale, wollige, cremefarbene bis graue Areolen aus denen 4 bis 8 1,5 bis 3 cm lange Mitteldornen entspringen. Die 10 bis 16 nadelförmigen, unregelmäßig angeordneten Randdornen sind weiß bis grau und 1 bis 2 cm lang.
Die trichterförmigen Blüten erscheinen um den Scheitel und weisen eine Länge und einen Durchmesser von bis zu 2,5 cm auf. Meist sind die Blütenhüllblätter gelb bis bräunlich, selten auch rosa. Die Blühperiode ist April bis Mai. Die zylindrisch bis ovalen Früchte sind 1,2 cm lang und haben einen Durchmesser von 8 mm. Sie enthalten 3 bis 15 graue, braune bis fast schwarze Samen, die innerhalb von 4 bis 6 Wochen reifen.
Pediocactus sileri ist endemisch im Grenzgebiet von Arizona und Utah in den Countys Mohave, Coconino, Washington und Kane in Höhenlagen zwischen 800 und 1500 Metern verbreitet. Er wächst in gipshaltigem Substrat auf flachen Hügeln und ist vergesellschaftet mit Sclerocactus parviflorus, Navajoa peeblesiana subsp. fickeiseniorum, Escobaria vivipara var. arizonica sowie verschiedenen Opuntia- und Yucca-Arten.
Die Erstbeschreibung erfolgte 1896 durch den amerikanischen Botaniker John Merle Coulter, der den von George Engelmann vergebenen Namen Echinocactus sileri verwendete.[1] Nathaniel Lord Britton und Joseph Nelson Rose stellten diese Art 1922 als Utahia sileri in die von ihnen neu geschaffene monotypische Gattung Utahia.[2] Lyman David Benson ordnete sie 1961 unter ihrem heutigen Namen Pediocactus sileri der Gattung Pediocactus zu.[3]
Pediocactus sileri ist die Typusart der Sektion Rhytidospermae, deren Mitglieder die typische, wellige Samenstruktur der äußeren Testa aufweisen.
In der Roten Liste gefährdeter Arten der IUCN wird die Art als „Least Concern (LC)“, d. h. als nicht gefährdet geführt.[4]
Pediocactus sileri:
Pediocactus sileri ist eine Pflanzenart der Gattung Pediocactus in der Familie der Kakteengewächse (Cactaceae). Das Artepitheton der Art A. L. Siler, der die ersten Pflanzen entdeckte. Englische Trivialnamen sind „Gypsum Cactus“ und „Siler´s Pincushion Cactus“.
Die Art ist bedroht und wurde in den Anhang I des Washingtoner Artenschutzabkommens zum Schutz gefährdeter Arten aufgenommen.
Pediocactus sileri is a rare species of cactus known by the common names Siler's pincushion cactus and gypsum cactus (or gypsum plains cactus). It is native to southwestern Utah and northwestern Arizona in the United States. It is limited to a specific type of soil, individuals are often spaced far apart, and the species is threatened by a number of human activities such as off-road vehicle use, poaching, and uranium mining.[2] This is a federally listed threatened species of the United States.
This cactus is egg-shaped or sometimes cylindrical in shape, and may have short branches. It is up to 25 centimeters tall by about 11 cm wide. The surface is bumpy with areoles which are covered in hairs or woolly fibers. Each areole has 3 to 7 main spines which are black to gray or white in color, those occurring near the base of the cactus body reaching up to 3 centimeters long. Each areole also has many smaller white spines 1 or 2 centimeters long. Spines around the base of the cactus may help to anchor it to the soil. The cactus flowers in April and May. The flower is up to 2 centimeters long by 3 cm wide and has white-margined brown outer tepals and purple-veined yellow inner tepals. The fruit is yellow-green in color and just over a centimeter long.[3]
The names Pediocactus sileri and Sclerocactus sileri have a confused relationship in the literature. (Pediocactus at one time included Sclerocactus, although they are now thought not to be closely related.)[4] According to the treatment in the Flora of North America,[3] the taxon described here was first described as Echinocactus sileri in 1896 and transferred to Pediocactus sileri by L.D. Benson in 1961.[5] Quite separately, L.D. Benson (in 1969) named a variety sileri of Sclerocactus pubispinus, which was raised to a full species under the name Sclerocactus sileri by K.D. Heil and J.M. Porter in 1994.[6] The two taxa are treated as two separate species in the Flora of North America, which has entries for:
Mistakenly, Anderson (2001) describes only one species, under the name Sclerocactus sileri, treating Pediocactus sileri as a synonym.[8] His description largely matches the description of Pediocactus sileri in the Flora of North America, and he uses the same common names (gypsum cactus, Siler's pincushion cactus) although the distribution he gives ("a very restricted area in Coconino County, Arizona") corresponds to that of Sclerocactus sileri in the Flora of North America ("restricted to northeast Coconino County, Arizona").[7]
The cactus grows on sand and clay substrate that is part of the Moenkopi Formation, a geologic formation, especially the Schnabkaib Member of the formation.[9] The soils are rich in gypsum and salts. Habitat in the area includes desert scrub, woodlands, and grasslands.[2] Most of the land is under the stewardship of the Bureau of Land Management.[9] The plant's distribution covers parts of Coconino and Mohave Counties in Arizona and Washington and Kane Counties in Utah.[2] Though the current total population of the cactus is unknown and has not been estimated, there have been over 10,000 individuals documented over a territory measuring just over 34,000 acres (140 km2).[9]
Threats to this species include uranium exploration. As the price of uranium has increased recently, mining claims have also increased in number.[9] All occurrences of the cactus occur on land that has potential for uranium discovery. Plans for uranium mining have often been modified to avoid damage to the cactus, but the threat still exists. Petroleum exploration and gypsum mining are considered future threats in the area, but not current ones. Off-road vehicles are popular in the local landscape, and there are designated roads for such activity and areas that are closed to vehicles for the protection of the plant. Grazing of livestock is considered a threat, but a minor one. Natural threats include drought and predation by rodents and rabbits.[9]
Conservation activities include the establishment of the White Dome Nature Preserve in Utah, which protects land that is home to the cactus, as well as to the rare dwarf bear claw poppy (Arctomecon humilis) and animals such as the zebra-tailed lizard (Callisaurus draconoides) and the loggerhead shrike (Lanius ludovicianus).[10]
Pediocactus sileri is a rare species of cactus known by the common names Siler's pincushion cactus and gypsum cactus (or gypsum plains cactus). It is native to southwestern Utah and northwestern Arizona in the United States. It is limited to a specific type of soil, individuals are often spaced far apart, and the species is threatened by a number of human activities such as off-road vehicle use, poaching, and uranium mining. This is a federally listed threatened species of the United States.
Pediocactus sileri (Engelm. ex J.M.Coult.) L.D.Benson es una especie de planta fanerógama de la familia Cactaceae.
Es endémica de Estados Unidos en Arizona y Utah. Su hábitat natural son los áridos desiertos. Es una especie rara en la vida silvestre. Se encuentra asociada con Sclerocactus parviflorus, Navajoa peeblesiana subsp. fickeiseniorum, Escobaria vivipara var. arizonica, y con especies de Opuntia y Yucca.
Es una planta de color gris a azul-verdoso, por lo general solitaria, a veces en grupos que forman cuerpo de la planta siendo esférica a oval y cilíndrica con la edad. Alcanza un tamaño de 5 a 20 cm (raramente 30 cm) de altura y un diámetro de 5 a 12 cm. Las costillas son cónicas, redondas u ovaladas, las areolas lanosas, de color crema a gris con 4 al 8 espinas centrales de 1,5 a 3 cm de largo. Las 10 a 16, espinas radiales están irregularmente dispuestas en forma de agujas y son de color blanco a gris con 1 a 2 cm de largo. Las flores en forma de embudo aparecen alrededor de la corona y tienen una longitud y un diámetro de hasta 2,5 cm. La mayoría son de color amarillo a marrón, rara vez de color rosa. El período de floración es de abril a mayo. El fruto es cilíndrico a oval de 1,2 cm de largo y tiene un diámetro de 8 mm. Contienen de 3 a 15 semillas de color gris, marrón a casi negro que maduran en 4 a 6 semanas.
Pediocactus sileri fue descrita por (Engelm. ex J.M.Coult.) L.D.Benson y publicado en Cactus and Succulent Journal 33(2): 53. 1961.[2]
Pediocactus: nombre genérico que deriva de las palabras griegas: "pedion" - lo que significa "llanura" - por las Grandes Llanuras de los Estados Unidos donde se encuentran las plantas.
sileri: epíteto otorgado en honor de A,L,Siler quien descubrió la planta.
Pediocactus sileri (Engelm. ex J.M.Coult.) L.D.Benson es una especie de planta fanerógama de la familia Cactaceae.
Vista de la plantaPediocactus sileri là một loài thực vật có hoa trong họ Cactaceae. Loài này được (Engelm. ex J.M. Coult.) L.D. Benson mô tả khoa học đầu tiên năm 1961.[1]
Pediocactus sileri là một loài thực vật có hoa trong họ Cactaceae. Loài này được (Engelm. ex J.M. Coult.) L.D. Benson mô tả khoa học đầu tiên năm 1961.