| | The genera of Cactaceae |
Sweet potato cactus.
Including Mirabella F. Ritter, Monvillea Britton & Rose, Piptanthocereus (A. Berger) Riccob., Subpilocereus Backeb.,
The plants cerioid; not ‘low and very compacted’. The stems spiny (usually), or not spiny; elongate cylindric; neither cephaliate nor pseudocephaliate. The plants branched; prostrate (rarely), or prostrate to erect, or erect; shrubby, or tree-like; with well formed trunks (often), or not developing conspicuous trunks; to (0.4–)1–15 m high. The stems columnar, or not columnar. The branches differing in form from the main stem to resembling the main stem. The main stem remaining dominant (often), or not remaining dominant; more or less cylindrical. The branches cylindrical, or angled. The stems segmented, or not segmented; strongly ribbed and grooved (or angled). The ribs 3–14; longitudinal. The grooves wide. The plants usually more or less conspicuously tuberculate, 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 not tubercle-associated (e.g., the ribs sometimes merely wavy marginally - e.g., C. jamacaru); closely approximating to distant; borne in longitudinal series; simple. The flowering areoles differing in form from the non-flowering ones (C. mortensenii), or resembling the non-flowering ones. The areoles usually without hairs; usually woolly; without glochids; with spines (often), or without spines. The spines clustered; 1–15; 0.2–20 cm long; with radials and centrals differentiated (often, the radials often shorter), or showing little or no difference between radials and centrals. Central spines when manifest, 1–5 (sometimes absent). Radial spines 3–12. The mature stems leafless.
Flowering at night, or at night and during the day. The flowers solitary; lateral; one per areole; usually very elongate- tubular; sessile; minute to large; 3–30 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The hypanthial tube and pericarpels elongate, thick; naked, or not naked; with scales (a few, scattered), or without scales; spineless. The perianth segments elongate; usually green and white (the outermost segments green), or white and red (rarely); limb relatively large. The perianth segments elongate, relatively narrow to relatively short, broad; blunt, or pointed, or acuminate. Stamens numerous; adnate to the perianth (inserted in the tube and throat).
The mature fruit 3–13 cm long; globose, or ovoid to ellipsoidal; red (usually), or yellow (sometimes); naked; with persistent floral remains; with the style alone persisting after the other floral remains have fallen; fleshy; dehiscent; dehiscing vertically by one slit (along one side). The seeds large, curved-ovoid, black; curved; not encased in bony arils; with hilum and micropyle conjunct. The testa shiny; unevenly verrucose. Cotyledons reduced or vestigial.
Natural Distribution. Eastern South America, Caribbean.
Classification. About 35 species. Subfamily Cactoideae. Tribe Cereeae.
Cf. Hunt, 1967.
Images. • Cereus aethiops: © Zoya© Zoya Akulova (2007). • Cereus aethiops: © Zoya Akulova (2007). • C. validus (with ‘Monvillea cavendishii’, cf. Praecereus saxicola?): Britton & Rose (1920). • Cereus insularis (as Monvillea): Britton & Rose (1920). • Cereus spegazzinii (as Monvillea), habit: Britton & Rose (1920). • cf. Cereus hildemannianus (as C. alacriportanus), with C. peruvianus (= C. hildemannianus or C. repandus?): Britton & Rose (1920). • Cereus fricii (as Cephalocereus russelianus): Britton & Rose (1920). • Cereus paxtonianus, cf. Monvillea cavendishii: Bot. Mag. 125 (1899).
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’.
