| | The genera of Cactaceae |
The plants succulent; condensed-cactoid (with tuberous roots); low and very compacted in their entirety. The plants’ appearance dominated neither by crowded areolar structures nor by tubercles covering the areoles. The stems spiny; discoid, or globose, or shortly cylindric; 1–22 cm in diameter; scarcely apically depressed to not apically depressed; neither cephaliate nor pseudocephaliate. The plants unbranched, or branched (sometimes many stemmed); erect; solitary to clustering; to 0.05–0.32 m high. The stems not segmented; ribbed and grooved. The ribs 12–30; longitudinal. The grooves deep and narrow. The plants conspicuously tuberculate, or not conspicuously tuberculate. The tubercles when present, connected by the ribs; borne in longitudinal series. The areoles not tubercle-associated, or not tubercle-associated (but the ribs notched); distant; borne in longitudinal series; simple (elongate). The flowering areoles resembling the non-flowering ones. The areoles without glochids; with spines. The spines clustered; 16–36; 1.5–2.5 cm long; with radials and centrals differentiated (the centrals erect and somewhat longer, the radials pectinately arranged). Central spines 1–3. Radial spines 15–30. The spines straight, or curved (?). The mature stems leafless.
Flowering during the day (?). The flowers often forming rings,sub- terminal to lateral; one per areole; funnelform to campanulate; sessile (?); small to medium-sized; 2–3 cm long (and 1.5–2.2 cm in diameter); regular. The receptacle scarcely produced beyond the ovary (very short); not naked; with scales; spineless. The pericarpel with small scales, slightly woolly in the axils. The hypanthial tube not naked; with scales (these small). The axils of the scales of the hypanthial tube not naked (slightly woolly). The hypanthial tube spineless. The perianth yellow, or red to pink. The perianth segments more or less erect and spreading (the inner parts erect, the outer spreading); pointed. Stamens adnate to the perianth (inserted in the throat and tube, the lowermost arising from a collar partially enclosing the nectar chamber); and style not exserted.
The mature fruit to 2.5 cm long; more or less globose, or clavate; yellow, or brown, or red; not naked (with small scales); without spines; with persistent floral remains; fleshy. The seeds dullish reddish brown, or black; helmet- or hat-shaped ("helmet"); not encased in bony arils. The testa rugose and pitted (irregularly pitted). Cotyledons reduced or vestigial.
Natural Distribution. Andean Peru.
Classification. 2 species. Subfamily Cactoideae. Tribe Trichocereeae.
Cf. Hunt (1967).
Images. • Oroya peruviana: © Zoya Akulova (2009).
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’.
