Pediocactus sileri (Engelm.) L. Benson (redirected from: Echinocactus sileri)
Family: Cactaceae
siler pincushion cactus,  more...
[Echinocactus sileri Engelm. ex J.M.Coult.,  more]
Pediocactus sileri image
Tony Frates  
Plants few branched or un-branched. Stems depressed-ovoid or occasionally elongate-cylindric, 5-15(-25) × 6-11.5 cm; areoles circular to pyriform, villous to lanate. Spines distin-guishable as radial and central: radial spines 11-15 per areole, white, 11-21 mm; central spines 3-7 per areole, nearly porrect, brownish black aging to pale gray or white, straight or slightly curving at tips, 13-30 × 1 mm at base. Flowers 0.8-2.2 × 2-3 cm; scales long fringed; outer tepals brown with white margins, long fringed, 9-15 × 3-4.5 mm; inner tepals yellow with purple veins, 15-20 × 4.5-6 mm. Fruits greenish yellow, short cylindric, 12-15 × 6-9 mm. Seeds gray to nearly black, 3.5-5 × 3-3.5 mm, papillate and rugose. Flowering spring. Rounded hills in gypsum clay and sandy soils of Moenkopi Formation, Great Basin desert scrub; of conservation concern; 900-1600 m; Ariz., Utah. Pediocactus sileri stems tend to develop a basal thatch of spines that anchor it to the fine, gypsum-rich soil. This species is endemic to a narrow strip along the Arizona-Utah border.

Plant: STEMS usually solitary or a few in clusters, depressed-ovoid, ovoid, or occasionally elongate-cylindrical, 5-15(-25) cm long, 6-11.5 cm in diameter, apex of the stem 3-11(-20) cm above soil surface; tubercles truncate-conical, 9-12 mm long, 6-11 mm in diameter, older tubercles dry, corky, compressed and persistent; areoles circular, woolly Leaves: SPINES densely covering the stem, the older spine clusters frayed, weathered, persistent and forming a thatch at the base of the stem; central spines 3-5(-7), 1.3-3 cm long, mostly 1 mm wide at the base, brownish-black aging to pale gray or white, nearly porrect, straight or slightly curving at the tips, acicular, nearly circular in cross section; radial spines 11-15, 1.1-2.1 cm long, white Flowers: up to 2.2 cm long, about 2.5 cm wide; outer tepals brown with white fringes; inner tepals yellow, obovate-oblanceolate, 1.5-1.9 cm long; 4.5-6 mm broad, minutely denticulate; stigma lobes yellow Fruit: FRUITS greenish-yellow, 1.2-1.5 cm long, 6-9 mm in diameter, scales present, cylindrical, dehiscing by a vertical slit. SEEDS gray to black, finely papillate and rugose, obliquely pyriform, 3.5-5 mm long, 3-3.5 mm wide Misc: Desertscrub; 1500 m (5000 ft.); May REFERENCES: Heil, Kenneth D., and Mark J. Porter. 2001. Cactaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1)
Pediocactus sileri image
Daniela Roth  
Pediocactus sileri image
Daniela Roth  
Pediocactus sileri image
Daniela Roth  
Pediocactus sileri image
Daniela Roth  
The National Science Foundation
This project made possible by National Science Foundation Award 1410069