Origin and Habitat: USA, Arizona (Southern portion of Navajo County, Apache County) New Mexico (southeast Rio Arriba County and McKinley County to Grant and Dona Ana counties) Texas (Hudspeth County) Colorado and Mexico. Sclerocactus papyracanthusSN|13716]]SN|13716]] is inconspicuous and probably irregular in occurrence, but quite abundant, at least in parts of range (6-20 occurrences globally reported); it may be more widespread than presently known.
Altitude range: 1,000 to 2,200 metres above sea level.
Habitat and ecology: Sclerocactus papyracanthusSN|13716]]SN|13716]] grows in red sandy soils of open flats in desert grasslands, in salt flats and gypsum habitats often among perennial bunchgrasses such as blue grama (Bouteloua gracilis), galleta (Hilaria jamesii), Sporobolus airoides, Pleuraphis muticus and juniper-pinyon woodlands. Most agree that many populations are probably in decline, some severely so due to degradation of habitats for urbanization, collection and development. However Sclerocactus papyracanthusSN|13716]]SN|13716]] has a relatively wide range, is abundant, has no major threats, is artificially propagated, and occurs within protected areas. These cacti are small and commonly overlooked, particularly because they typically grow in or near clumps of grama grass, and the cactus plants themselves have central spines that resemble dried leaf blades. In ungrazed areas where the species occurs, tall plants are fairly common; where grazing is moderate, they are far less frequent and trampled plants are often seen. Trampling, probably the major direct effect of livestock with regard to this cactus, also compacts the soil. Seedlings, always cryptic and difficult to see, are most frequently found in rather loose soil. Light grazing may open grass cover slightly and facilitate seedling establishment. More intensive grazing potentially exposes plants to increased predation by small herbivores, which would seek alternate food items as other forbs are eaten by livestock. Second, the loss of grass cover results in erosion of topsoil, thereby accelerating loss of sites for seedling establish-ment and hastening population decline. Its highly inconspicuous nature combined with the ubiquity of its potential habitat make it difficult to study and estimate the seriousness of decline. In Texas the taxon surely ranks with Ancistrocactus brevihamatusSN|3503]]SN|3503]] var. pallidus as being either rare or so well camouflaged that it appears to be rare.

• Sclerocactus papyracanthus (Engelm.) N.P.Taylor
• Echinocactus papyracanthus (Engelm.) Engelm.
• Mammillaria papyracantha Engelm.
• Pediocactus papyracanthus (Engelm.) L.D.Benson
• Toumeya papyracantha (Engelm.) Britton & Rose

• Sclerocactus papyracanthus (Engelm.) N.P.Taylor
• Echinocactus papyracanthus (Engelm.) Engelm.
• Mammillaria papyracantha Engelm.
• Pediocactus papyracanthus (Engelm.) L.D.Benson
• Toumeya papyracantha (Engelm.) Britton & Rose

• Sclerocactus papyracanthus cv. Curly Spines
• Toumeya papyracantha cv. Curly Spines

Description: The Grama Grass Cactus Sclerocactus papyracanthusSN|13716]]SN|13716]], best known as Toumeya papyracanthaSN|13720]]SN|13720]] is a tiny solitary cactus, rarely branched from the base in old age, with very characteristic flattened centrals spines resembling dried grass leaves or wood shavings. The main central spine, the longest and widest, is the lower central. The main central is flat, thin, flexible, curved, and often twisted.
Stem: Dark green, cylindroid or slightly obconic, 2,5-7.5 ( or more) cm tall and 1-2(-4) cm in diameter. It has no ribs and tubercles are elongate, 1.5-5 mm long, dark grey-green, rather soft but usually is obscured by the spines;.
Stem anatomy: The stele is particularly thin, usually 2 mm or less in diameter, without medullary vascular system. Large mucilage cells occur in the tubercles and in the cortex, but are not present in the pith. Tissues which have mucilage cells are conspicuously slimy when freshly cut.
Roots: Fibrous 5-10 cm long.
Areoles: 1-2 mm in diameter at the summits of the tubercles, and generally 0.3 cm apart. Glands, which are homologous with spines, are pale reddish to tan, frequently on the adaxial sides of areoles which do not produce flowers. Areoles at the stem apex produce yellowish wool.
Central spines: Usually 1-2 (occasionally 3-4), whitish or pale brown to gray, erect or ascending, lacking hook, strongly flattened and thin, flexible, grooved, often twisted or curled, papery in texture, (12-)18-27(-38) mm long (to 4-5 cm long in cultivation), 0.4-2 mm wide. often obscuring the surface of the stem.
Radial spines: Parallel to the stem surface, 6-9 per cluster, silvery-white to ashy-white, flexible, flattened, straight, appressed, about 2-5 mm long, 0.3-0.6 mm wide. The longest radials, to 5 mm, are the lowermost ones.
Flower: On the new growth of the current season near the apex of the stem. Whitish, funnelform to narrowly bell-shaped, 18-25 mm long, ca. 1-2.5 cm wide. Inner perianth segments white with pale brown midstripes, largest ones about. 2 cm long, and 4 mm in diameter apex acute to mucronat. Outer perianth segments cuneate-spatulate, usually 9-20 lomg, with a green-purple to brownish central midstripe, and whitish margins, to 2 cm long, 3 mm wide. Filaments whitish to greenish yellow. Anthers cream-colored. Style greenish to cream-coloured, to 2 cm long. Stigma lobes 4-5, cream-coloured or pale green, 1.5 mm long. Pericarpel with or without scale bracts, spines also occasionally present in pericarpel areoles.
Fruit: Green, often changing to tan, spherical, 4.5-7 (or more) mm long, up to 4.5 mm wide dry and dehiscent at maturity along a dorsal slit and around the circumscissile apex; scales few or none, floral remnant persistent.
Seeds: Quite large, broadly obovoid, slightly flattened, (2.5-3 mm long, 2-2.5 mm wide, ca. 1 mm thick) black, shiny; testa with fine, rounded papillae.Hilum relatively small.
Phenology: Blooming time April/May. The flowers opened relatively late in the after-noon, between 3:00 and 4:00 P.M., closed at night, and opened again for 5-6 days.
Immature specimens: Stems of young Sclerocactus papyracanthusSN|13716]]SN|13716]] are very slender, sometimes remaining less than 6 mm in diameter when 2-3 cm long. The spines of juveniles are similar to those in adults except that the central spines are relatively short.

Notes: Toumeya papyracanthaSN|13720]]SN|13720]] might be a neotonous derivative of Sclerocactus. This supports the recommendation by the IOS Working Party (Hunt and Taylor, 1986) that Toumeya be treated as a synonym of Sclerocactus. Chloroplast DNA analyses of J. M. Porter et al. (2000) unambiguously placed this species within Sclerocactus.

Bibliography: Major references and further lectures
1) Fritz Hochstätter “Tribe Cacteae, Family Cactaceae: The genera Pediocactus Navajoa Toumeya” Hochstätter, 2005
2) Heil, K., Terry, M. & Corral-Díaz, R. 2013. Sclerocactus papyracanthus. The IUCN Red List of Threatened Species 2013: e.T152367A628965. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T152367A628965.en. Downloaded on 30 January 2016.
3) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
4) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
5) 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
6) William A. Dick-Peddie, William H. Moir, Richard Spellenberg “New Mexico Vegetation: Past, Present, and Future” UNM Press, 01 November 1999
7) A. Michael Powell, James F. Weedin “Cacti of the Trans-Pecos & Adjacent Areas” Texas Tech University Press, 2004
8) “Sclerocactus papyracanthus” in Flora of North America @ efloras.org <http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242415297> FNA Vol. 4 Page 197, 198, 203, 205, 206, 207. web 30 January 2016
9) Leo J. Chance “Cacti and Succulents for Cold Climates: 274 Outstanding Species for Challenging Conditions” Timber Press, 19 June 2012
10) Lyman David Benson “The Cacti of the United States and Canada” Stanford University Press, 1982
11) Wikipedia contributors. "Sclerocactus papyracanthus." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 8 Nov. 2015. Web. 30 Jan. 2016.
12) Matthews, Robin F. 1994. Pediocactus papyracanthus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). <http://www.fs.fed.us/database/feis/plants/cactus/pedpap/all.html> web 30 January 2016
13) Weniger, D. "Cacti of the Southwest". Austin, TX: University of Texas Press.1970.
14) “Toumeya gen. nov.” In: N. L. Britton, J. N. Rose: “The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family.” volume 3, Washington 1922

Cultivation and Propagation: It needs moderate watering, because excess of water causes mature individuals to rot and die, especially after transplanting.
Sun Exposure: Full sun to partial shade.
Cultural Practices: Needs a very draining and mineral substratum.
Frost Tolerance: Very frost hardy, above approx -12° C.
Propagation: Seeds: Temperature for optimum germination: night minimum approx 17 day maximum, up to nearly 40 C, at any time of year with proper temperatures and daylength (ca.13-14 hours); it is possible to extend day-length with artificial lights. Anyway the seeds germinate slowly with extreme difficulty and a low rate of success. scarification and stratification help, alternately freeze and thaw both wet and dry, but don’t keep wet, alternate wet and dry with changing temperatures. Germination can take several years, so keep pot and try again next year. Seedlings do not do well either, and some die each year, for this reason plants are commonly grafted on hardy stocks liOpuntia humifusaSN|11629]]SN|11629]]usa. In this case they are easy to grow and no special skill is required.