Origin and Habitat: Brumado, Ourives, Palma de Monte Alto and adjacent areas, Bahia, Brazil

• Melocactus zehntneri subs. canescens (Buining & Bredero) P.J.Braun
• Melocactus canescens F.Ritter

• Melocactus zehntneri (Britton & Rose) Luetzelb.
• Cactus zehntneri Britton & Rose
• Melocactus canescens var. montealtoi F.Ritter
• Melocactus giganteus Buining & Bredero
• Melocactus helvolilanatus Buining & Bredero
• Melocactus macrodiscus Werderm.
• Melocactus saxicola Diers & Esteves
• Melocactus zehntneri var. ananas Rizzini
• Melocactus zehntneri subs. arcuatispinus (Bredero & Eerkens) P.J.Braun & Esteves
• Melocactus arcuatispinus Bredero & Eerkens
• Melocactus zehntneri subs. canescens (Buining & Bredero) P.J.Braun
• Melocactus canescens F.Ritter
• Melocactus zehntneri var. curvicornis (Buining & Bredero) P.J.Braun
• Melocactus curvicornis Buining & Bredero
• Melocactus zehntneri f. douradaensis (Hovens & Strecker) Delanoy
• Melocactus douradaensis Hovens & Strecker
• Melocactus zehntneri var. viridis F.Ritter

Description: Melocactus zehntneriSN|20575]]SN|20575]] subs. canescens is one of the local form of the very variable Melocactus zehntneriSN|20575]]SN|20575]] distingusced from the standard species for it somewhat short cylindrical, often globular, stems with about 15 ribs. There are about seven stout brownish-gray radial spines, one central and the cephalia are densely covered by orange red bristle.
Habit: Usually stay solitary, mature plants are easily recognizable by their cephalia, that have a covering of wool and orange or red bristles, The immature plant looks like a smallish barrel cactus, and there is nothing in its appearance that would suggest a melocactus.
Stem: Strongly longitudinally ribbed depressed-globose or spheroid to cylindrical, pale to dull green, often glaucous, 10-50 cm high, 9-25 cm in diameter.
Ribs: 10-16 (rarely to 19) sharply acute.
Areoles: 1,2-2 cm apart.
Cephalia: 6-11 cm or more long, 6-10 cm in diameter, with dense, fine, pale pinkish red bristles and sparse or abundant white to creamy white wool.
Spines: Rather stout, yellow, brown, or reddish, overlaid with grey except at the dark tips.
Central spines: Usually 1 curved upward.
Radial spines: mostly 7, weakly to strongly curved backward, lower ones longest.
Flowers: Small inconspicuous (15-25 mm long, 4-13 mm across) pale to deep or purple, self pollinating, growing even with or well exserted at the top of the cephalium.
Fruit: Clavate, white or pale to deep lilac-pink, 12-20 mm long 4-8 mm in diameter.
Seeds: 1,2-1,3 x 1-1,1 mm noticeably tuberculate at end opposite hilum.

Bibliography: Major references and further lectures
1) Stuart Max Walters “The European garden flora. 3.[Angiospermae], Dicotyledons. [Casuarinaceae to Aristolochiaceae]” Cambridge University Press, 1989
2) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
3) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
4) Urs Eggli, Leonard E. Newton "Etymological Dictionary of Succulent Plant Names" Birkhäuser 2004
5) Taylor, N. P. 1991. "The genus Melocactus (Cactaceae) in Central and South America." Bradleya 9: 1–80.
6) Nigel Taylor, Nigel P. Taylor, Daniela C. Zappi, “Cacti of Eastern Brazil” Royal Botanic Gardens, Kew, 15/gen/2004
7) Edgar Lamb, Brian Lamb “The Illustrated Reference on Cacti & Other Succulents” Volume 5 Blandford Press, 1978
8) E Haustein “Der Kosmos Kakteenfuehrer (the Kosmos Cactus Guide)” Balogh Scientific Books 01 December 1998
9) Clive Innes, Charles Glass “Cacti” Portland House, 1991
10) Machado, M., Taylor, N.P., Braun, P. & Zappi, D. 2013. Melocactus zehntneri. In: “IUCN 2013. IUCN Red List of Threatened Species.” Version 2013.2. <www.iucnredlist.org>. Downloaded on 04 December 2013.