Publication: Succulenta (Netherlands) 71: 253, fig. 1992
Description
Sclerocactus nyensis commonly known as the Nye County fishhook cactus, is a rare cactus species with reddish spines that may or may not be hooked. The rose-colored flowers appears in spring.
Habit: Sclerocactus nyensis grows solitary stems and sometimes forms a cluster of two or three stems. In habitat it is normally invisible, except when in flower or after good rains. Older plants eventually lose the ability to retract.
Stem: Spheric, cylindric, or elongate-cylindric, 5-12(- 16) cm long, 4-8(-10) cm in diameter.
Ribs: Distinct, 12-15, with well-formed tubercles.
Spines: Dense, obscuring stems.
Central spines: (1-)4-7(-8) per areole, lower and lateral ones red or reddish brown and usually hooked 20-60 mm long, upper ones flat white, straight and rarely hooked 25-45 mm long.
Radial spines: 12-17, whitish, flat, straight, (8-)10-17(-20) mm long.
Flowers: Funnelform to campanulate, rose-coloured to magenta 3-4 cm long, 2-2.5 cm across. Outer tepals with greenish purple midstripes and rose-purple or magenta margins, cuneate-spatulate, usually 10-17 mm long and 5-8 mm wide; inner tepals rose-purple to magenta, largest tepals ovate-lanceolate, 18-22 mm long 6-8 mm wide; filaments green to yellow; anthers cream to yellow.
Blooming season: Spring (in habitat the flowering period begins in May).
Fruits: Barrel shaped, 15-20 long, 7-15 mm across, green to tan, dry at maturity, indehiscent or irregularly dehiscent.
Seeds: 3-3.5 mm long, 2 mm wide, black, irregularly furrowed; testa with rounded papillae.
Similar species: S. nyensis exhibits considerable morphologic variation across the range. Some plants look like Sclerocactus blainei, Sclerocactus pubispinus, and Sclerocactus spinosior, but differ in the higher number of central spines (six to eight), and more or less indehiscent fruit. In some sites S. nyensis overlap populations of Sclerocactus polyancistrus, but different flowering time likely prevents hybridization. DNA study from the chloroplast genome of species of Sclerocactus provide evidence that Sclerocactus blainei - but not the southwestern population, Sclerocactus nyensis - and Sclerocactus pubispinus, Sclerocactus schlesseri, and Sclerocactus spinosior share several mutations unique in the genus. This at once provides evidence for the common ancestry of Sclerocactus blainei, Sclerocactus pubispinus, Sclerocactus schlesseri , and Sclerocactus spinosior, and of the independence (species status) of Sclerocactus nyensis. DNA analyses provided evidence that S. nyensis is the sister taxon to Sclerocactus papyracanthus.
Origin and Habitat
Sclerocactus nyensis has a narrow range (extent of occurrence is 1,300 km2) in Nye and Esmeralda Counties, southern Nevada, USA.
Altitude: 1500-1800 metres above sea level.
Habitat and Ecology: The species is native to the mountainous terrain of southern Nevada where it occurs in a very dry area with annual precipitation of around 100 mm. It grows on soils derived from volcanic ash, on hills and slopes in Mojave desert scrub and saltbush-dominated flats together with Sclerocactus polyancistrus, Escobaria vivipara var desertii, Micropuntia sp. and Yucca brevifolia. The species is locally uncommon and scattered. The populations have been endagered by gold mining activities and has no protection.
Cultivation and Propagation
Sclerocactus nyensis is very rare in cultivation, it is difficult to grow on its own roots and to propagate, but continues to be a particular prize among specialist collectors. Mature individuals easily rot and die especially after planting. The seeds germinate with extreme difficulty and a low rate of success, seedlings do not do well either, and more die each year.It is extremely xerophytic and adapted to very dry soils, but plants grafted on hardy stock (Opuntia humifusa, Echinocereus triglochidiatus etc…) are relatively easy to grow and no special skill is required, they can stay in a non heated greenhouse. (min tem -20°C). For the heated glasshouse Eriocereus jusbertii is the recommended stock. However, the grafted plants lose their natural appearance.
Propagation: Seeds are extremely difficult to germinate (only 2-3 percent of seeds germinate). The germination is really difficult and if some seedling finally sprout, as they start to grows they disappear one by one. Grafting is often used to speed growth rate and to create a back-up for plants in collection.
Bibliography
Major references and further lectures
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Butterworth, C. & Porter, J.M. 2013. Sclerocactus nyensis. In: IUCN 2013. “IUCN Red List of Threatened Species.” Version 2013.2. <www.iucnredlist.org>. Downloaded on 05 March 2014.
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Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
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James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug/2011
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David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. “The New Cactus Lexicon” dh books, 2006
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Urs Eggli, Leonard E. Newton: “Etymological Dictionary of Succulent Plant Names.” Birkhäuser 2004
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Lyman David Benson “The Cacti of the United States and Canada” Stanford University Press, 1982
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Fritz Hochstätter “An den Standorten von Pediocactus und Sclerocactus” Selbstverlag, 1989.
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Fritz Hochstätter: “The Genus Sclerocactus” Selbstverlag, 2005
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Leo J. Chance “Cacti and Succulents for Cold Climates: 274 Outstanding Species for Challenging Conditions” Timber Press, 19/giu/2012
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Flora of North America Editorial Committee “Flora of North America: North of Mexico.” Oxford University Press, 1993
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J. Mark Porter in: “Endangered Wildlife and Plants of the World”, Volume 2
Marshall Cavendish Corporation, 2001