| | The genera of Cactaceae |
The plants succulent; stout-rooted, cerioid to condensed-cactoid; low and very compacted in their entirety, or not ‘low and very compacted’. The stems spiny; ovoid to shortly cylindric; 2.5–5 cm in diameter; not apically depressed; neither cephaliate nor pseudocephaliate. The plants branched and offsetting (caespitose); prostrate and erect; clustering; to 0.07–0.3 m high. The branches to 0.07–0.3 cm long; 2.5–5 cm in diameter. The stems not segmented; ribbed and grooved. The ribs 10–15; longitudinal. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; fairly closely approximating; borne in longitudinal series; simple. The flowering areoles resembling the non-flowering ones. The areoles without glochids; with spines. The spines clustered; 11–50; 0.5–3 cm long; with radials and centrals differentiated (the centrals 20–30 mm long, the radials 5–20 mm long). Central spines 3–7. Radial spines 8–40. The spines stiff; straight. The mature stems leafless.
Flowering during the day. The flowers more or less terminal; one per areole; short-tubed, sub- campanulate; sessile; small to medium-sized; 1–2 cm long (1.5–2 cm in diameter); regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The pericarpel with small scales and axillary wool. The hypanthial tube not naked; with scales (these small). The axils of the scales of the hypanthial tube not naked (woolly). The hypanthial tube spineless. The perianth cream to yellow. The perianth segments relatively short, broad; pointed. Stamens not exserted.
The mature fruit 1.1–1.5 cm long; globose; green; "nearly" naked (!); with persistent floral remains; fleshy; indehiscent. The seeds small; black; semi-elliptic in outline"; not encased in bony arils. The testa shiny; verrucose. Cotyledons reduced or vestigial.
Natural Distribution. Adean central Peru.
Classification. 1 species, or 10 species (depending on interpretation of the variable M. caespitosa). Subfamily Cactoideae. Tribe Trichocereeae.
Cf. Hunt (1967).
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’.
