| | The genera of Cactaceae |
~ Echinofossulocactus, cf. Hunt (1967)
Including Echinofossulocactus Britton & Rose, Efossus Orcutt (orth. var.)
The plants condensed-cactoid; low and very compacted in their entirety. The plants’ appearance dominated neither by crowded areolar structures nor by tubercles covering the areoles. The stems very spiny; discoid to globose, or shortly cylindric; 4–12 cm in diameter; somewhat apically depressed to not apically depressed; neither cephaliate nor pseudocephaliate. The plants unbranched; erect; small; usually solitary; to 0.04–0.12 m high. The stems not segmented; ribbed and grooved. The ribs (10–)20–60(–120); longitudinal (sometimes wavy); acute. The grooves deep and narrow. The plants conspicuously tuberculate (sometimes), or conspicuously tuberculate to not conspicuously tuberculate, or not conspicuously tuberculate. The tubercles connected by the ribs; borne in longitudinal series. The areoles associated with tubercles, or associated with tubercles to not tubercle-associated (then with rib notches or thickening associated with the areoles); few on each rib, distant (widely spaced); borne in longitudinal series; simple; with spines. The spines clustered; 3–15(–26); 0.4–5(–8) cm long; with radials and centrals differentiated (more or less: in two series, the upper of large, often dagger-like members, the lower representing the radials); never hooked; straight, or curved (sometimes curved upwards). The mature stems leafless.
Flowering during the day (?). The flowers terminal; one per areole; shortly funnelform to campanulate; sessile; small to medium-sized; 1.5–4 cm long (where recorded). The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; not naked; with scales; spineless. The pericarpel with scales and naked aeoles. The hypanthial tube not naked; with scales. The scales of the hypanthial tube not spine-tipped. The axils of the scales of the hypanthial tube not naked (with naked areoles). The hypanthial tube spineless. The perianth white and pink, or white and brown (white with brownish or pinkish mid-veins). The perianth segments elongate, relatively narrow, or relatively short, broad; pointed, or apiculate. The androecium without staminodes. Stamens not exserted; not grouped. The stigma lobes white, or yellow.
The mature fruit usually globose; pale green; not naked (usually slightly scaly); without spines; non-fleshy when mature; dehiscent; dehiscing vertically by one slit ("along one side"). The seeds 1.4 mm long; brown to black; broadly oval; concave; not encased in bony arils. The testa shiny. Cotyledons reduced or vestigial.
Natural Distribution. Northern and central Mexico. Central America.
Classification. 10 species. Subfamily Cactoideae. Tribe Cacteae.
Images. • Stenocactus coptonogonus: © Zoya Akulova (2017). • Stenocactus crispatus (as Echinofossulocactus violaciflorus) and S. polyancistrus, with Parodia microsperma (as Hickenia) and P. ottonis (as Malacocarpus): Britton & Rose (1922).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2018 onwards. The genera of Cactaceae: descriptions, illustrations, identification, and information retrieval. Version: 14th November 2021. delta-intkey.com’.
