Origin and Habitat: Pediocactus nigrispinusSN|19717]]SN|19717]] occurs in Eastern Washington (Chelan to Yakima Counties), Eastern Oregon and West-Central Idaho in the United States. The species is locally abundant, however the distribution is sparse. Pediocactus nigrispinus is the Pediocactus species that reaches the northernmost and westernmost distribution.
Altitude range: This species grows in desert valleys to low mountains at low altitudes, from 400 to 1000 metres above sea level, all the other Pediocactus are high-altitude plants.
Habitat and Ecology: The species is found in gravelly soils and lava, in sage brush, grasslands, pinyon-juniper and conifer forests, also on rocky outcrops or on remote gravelly hillsides and boulder fields. The Opuntia erinaceaSN|31247]]SN|31247]] var. columbiana are found growing with Pediocactus nigrispinusSN|19717]]SN|19717]], although rarely. This species has already been eliminated by "cactus rustlers" from parts of its native habitat that are easily accessible, and in some places it is under threat from grazing and development, however no major threats are known and the population trend is stable. The species is available in the trade and is found is specialist collection.

• Pediocactus nigrispinus (Hochstätter) Hochstätter
• Pediocactus simpsonii var. nigrispinus Hochstätter

• Pediocactus nigrispinus (Hochstätter) Hochstätter
• Pediocactus simpsonii var. nigrispinus Hochstätter
• Pediocactus nigrispinus subs. beastonii (Hochstätter) Hochstätter
• Pediocactus nigrispinus var. beastonii Hochstätter
• Pediocactus nigrispinus subs. puebloensis Hochstätter

Description: Pediocactus nigrispinusSN|19699]]SN|19717]] is a rounded cactus that may be solitary or clump-forming, occasionally with over 50 heads, and forming large mounds to 30 cm or higher, and 60 cm across. The spines usually are reddish brown to nearly black, but variable in thickness, yet in their colour. The flowers are showy usually pink, but ranging from purple to white. Occasionally peach coloured or yellow flowers can be found as well. No known morphologic character supports the taxonomic recognition of infraspecific taxa within Pediocactus nigrispinusSN|14637]]SN|19717]]. Characteristics used to distinguish the three described subspecies almost completely overlap.
Derivation of specific name: In botanical Latin an adjective derived from 'niger' that means black, and 'spina' a spine, with black spines.
Stems: Globose and depressed to elongate-ovoid, single or in clumps, 5-30 tall, 5-15 cm thick, covered with tubercles 12-25 mm long, in 8-13 spiral rows.
Areoles: Oval, hairy.
Spines: Smooth, hard, and rigid, distinguishable as radial and central.
Central spines: 6-12, rigid, straight or slightly curved, widely spreading or nearly erect, 8-55 mm long, less than 1 mm diameter at base, reddish brown to nearly black, base yellow or cream. On some plants, the spines can also be grey or golden.
Radial spines: 10-30 per areole, smaller, spreading at right angles to tubercles nearly straight, white to dull reddish brown, 8-20 mm long.
Flowers: Showy - often 4-8 buds at the top of each stem – funnel-shaped, each at the tip of a tubercle, 1-3.5 long, 2.5-5 cm broad, red-violet to yellowish-green. Perianth segments and stamens numerous, all joined at the base. The scales on the tube and outer perianth segments of flower tube minutely toothed, laciniate, or entire and undulate. Outer perianth segments with greenish brown midstripes, oblong-cuneate, 12-25 mm long, 4.5-9 mm broad. Inner perianth segments white, pink, magenta, peach, yellow or yellow-green, 19-27 long, 5-10 mm broad. Ovary inferior, 1-celled.
Blooming season: The flowers open during the day, bloom in late spring to summer (May-July) and seeds are ripe one month later, though this can vary substantially depending on the weather.
Fruits: Fruit subglobose to short cylindric, 6-11 mm, 5-10 mm in diameter, green tinged with red, drying reddish brown.
Seeds: Grey to black, 2-3 long 1.5-2 mm thick, papillate but not rugose.
Taxonomy: Pediocactus nigrispinusSN|14459]]SN|19717]]is related to the smaller Pediocactus simpsoniiSN|14412]]SN|19699]], which is found in colder areas throughout the West and typically has white or nearly-white spines. Some botanists prefer to think of P. nigrispinus as a variety or subspecies of P. simpsonii, but in any case it is certainly quite a distinctive plant. P. nigrispinus usually has spines closer to black, though some variants with lighter whitish or golden spines are found. An unpublished study by J. M. Porter et al. of noncoding chloroplast DNA sequences shows P. simpsonii is less closely related to P. nigripsinus than to Pediocactus knowltoniiSN|19699]]SN|14412]], Pediocactus winkleriSN|19717]]SN|14459]], and Pediocactus despainiiSN|19717]]SN|14637]]. P. nigrispinus should be treated separately due to its unique appearance, with a dense covering of black spines. The name Pediocactus simpsoniiSN|19717]]SN|19699]] var. robustior is considered misapplied.

Bibliography: Major references and further lectures
1) Flora of North America Editorial Committee “Flora of North America: North of Mexico. Magnoliophyta: Caryophyllidae, part 1” Oxford University Press, 1993
2) Leo J. Chance “Cacti and Succulents for Cold Climates: 274 Outstanding Species for Challenging Conditions” Timber Press, 19 June 2012
3) Don Knoke, David Giblin “Pediocactus nigrispinus - snowball cactus” Burke Museum of Natural History and Culture. Web 24 January 2016
4) Unknown,“Pediocactus nigrispinus” in Flora of North America @ efloras.org <http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242415308> FNA Vol. 4 Page 214 accessed on 23 January 2016
5) Butterworth, C. & Porter, J.M. 2013. Pediocactus nigrispinus. The IUCN Red List of Threatened Species 2013: e.T152155A603646. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T152155A603646.en. Downloaded on 24 January 2016.
6) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
7) 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
8) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh Books, Milborne Port, UK., 2006
9) Text & Photos: Dixie Dringman “Pediocactus nigrispinus in the Colockum Game Range (WA, USA)” in: North-american Cacti Cactus & Co. – Globetrotter <http://www.cactiguide.com/cactus_co/Pediocactus_nigrispinus.pdf> web 24 January 2016
10) Text & Photos: Jean Bonnefond “Pediocactus: the early years of cultivation” North american cacti Cactus & Co. – cultivation <http://www.cactiguide.com/cactus_co/Pediocactus_cultivation.pdf> web 24 January 2016
11) Giblin, David. "Washington Flora Checklist." . University of Washington Herbarium, 8 12 2008. Web. 24 January 2016. <http://biology.burke.washington.edu/herbarium/waflora/checklist.php?Taxon=Pediocactus nigrispinus&ID=9684>.
12) Barclay, Ian. “Ian's Plant Expedition to Eastern Washington
July 19-21, 2005 ”. The Desert Northwest: N.p., 2005. Web. 24 January 2016.
<http://www.desertnorthwest.com/gallery/travel_0507_ewa/>
13) Dringman, Dixie A. “Washington State Cacti and their History.” Cactus & Co. publication, date unknown.
14) Ian Barclay. “A Primer on Washington Native Cacti” The desesert Northwest Web. 24 January 2016. >http://www.desertnorthwest.com/articles/native_cacti.html>