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Sclerocactus parviflorus subs. intermedius (Peebles) K.D.Heil & J.M.Porter

Family: CACTACEAE · Variety or form of Sclerocactus parviflorus

Publication: Haseltonia 2: 27. 1994

Description

Sclerocactus parviflorus subs. intermedius is a nice though diminutive barrel cactus with purple, rose, pink, or (rarely) white flowers. It is distinguished from Sclerocactus parviflorus by its long not hooked upper central spine flattened and to 1-1.5(-2) mm broad and by seeds at most 2.5 mm broad. It is somewhat intermediate in habit between Sclerocactus parviflorus and Sclerocactus whipplei and is quite variable over its wide range.

Stems: Spherical to cylindrical, to about 30 cm tall. It usually grows single but occasionally forms small clusters of 2-3 heads.

Ribs: 13-15 conspicuously tubercle. Tubercles 8-9 mm high.

Areoles: Circular at first, but growth of flower produces narrow extension upward, leaving areole elliptical or practically so, about 4-6 mm long, with much white wool.

Radial spines: 7-11 straight 12-24 mm long, all but 1 lower lateral on each side white, these 2 lower laterals grey or brownish.

Central spines: 4 on mature specimens, lowermost 1 porrect to slightly deflexed, strong, round to somewhat flattened, hooked, (17-)25-50(59) mm long, 0.5-1 mm diameter, white, grey or tan, dark brown, purplish-pink or black, usually streaked with white; 2 lateral centrals similar but straight; uppermost central 19-57 nm long, mostly 1.5-2 mm or less widee, rarely purple to pink, whitish, mostly angled, rarely flat or rhombic in cross-section, straight or nearly so.

Flowers: Beautiful, more or less funnel-shaped, mostly fuchsia but some-times purplish, pink, or (rarely) whitish and never yellow, about 2.5-5 mm diameter and length; ovary has a few short, greenish, triangular scales with membranous, crinkled edges and short hairs in axils; outer perianth segments greenish in midline, edges whitish, membranous, crinkled, to about 12 mm wide; inner perianth segments (tepals) fuchsia, purple, rose, pink, or whitish, lanceolate, edges entire or nearly so; green or yellowish filaments; orange anthers; pinkish or rose style and stigma with 5-6 lobes.

Blooming season (in habitat): May-June (late spring).

Fruits: Oblong, to about 12-25 mm long, green to pinkish and fleshy at first, surface with several scales; when ripe becoming dry and opening by splitting.

Chromosome number. 2n = 22.

Remarks: Sclerocactus whipplei var. reevesii is very similar to this taxon and often left as a synonym (Del Weniger 1984).

Origin and Habitat

Utah, Arizona, Colorado, and New Mexico.

Type locality: Pipe Springs, Mohave County, Arizona, USA

Altitude range: Sclerocactus parviflorus subs. intermedius is found mostly at mid elevations, 1350-2000 metres above sea level (occasionally up to 2200 metres).

Habitat and ecology: It occurs in the upper Navajoan Desert in pinyon-juniper woodland and blackbrush communities. It is adapted to extremely arid conditions and is extra-sensitive to moisture.

Cultivation and Propagation

Rarely seen in cultivation, it needs perfect drainage to flourish. It is quite difficult to grow on its own roots and to propagate (only 2-3 percent of seeds germinate ). Mature individuals easily rot and die.

It is indispensable to provide a greenhouse with good ventilation and full sun exposure. Keep totally dry during winter. It can tolerate temperature below zero (-20° C). Plants grafted on hardy Opuntia humifusa stock are quite easy to grow, and no special skill is required.

Propagation: Seeds are extremely difficult to germinate (only 2-3 percent of seeds germinate). Grafting is often used to speed growth rate and to create a back-up for plants in collection.

Bibliography

Major references and further lectures

  1. Fritz Hochstätter “Tribe Cacteae, Family Cactaceae: The genus Sclerocactus” Fritz Hochstätter, Selbstverlag, 2005

  2. Fritz Hochstätter “An den Standorten von Pediocactus und Sclerocactus.” Selbstverlag 1989.

  3. Del Weniger “Cacti of Texas and Neighboring States: A Field Guide” University of Texas Press, 1984

  4. Heil, Kenneth D., and Mark J. Porter. 2001. “Cactaceae.” J. Ariz. - Nev. Acad. Sci. Volume 33(1)

  5. Del Weniger “Cacti of the Southwest: Texas, New Mexico, Oklahoma, Arkansas, and Louisiana” University of Texas Press, 1969

  6. Leo J. Chance “Cacti and Succulents for Cold Climates: 274 Outstanding Species for Challenging Conditions” Timber Press, 19 June 2012

  7. Sclerocactus parviflorus subsp. intermedius (Peebles) Heil & Porter <http://swbiodiversity.org/seinet/taxa/index.php?taxon=Sclerocactus+parviflorus+var.+intermedius\>

  8. Checklist of CITES Species Part 1 CITES species index, 2011

  9. Sclerocactus parviflorus Clover & Jotter [family CACTACEAE] in Kenneth D. Heil, J. Mark Porter, Flora of North America, Vol 4

  10. Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001

  11. 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

  12. David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. “The New Cactus Lexicon” dh books, 2006

  13. Porter, J.M. 2013. “Sclerocactus parviflorus.” The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 21 December 2014.