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| The genera of Cactaceae |
Night-blooming cactus, Moonlight cactus.
Including Cryptocereus Alexander, Deamia Britton & Rose, Marniera Backeb., Mediocactus Britton & Rose, Strophocactus Britton & Rose, Strophocereus Fric & Kreuz. (orth. var.)
The plants non-laticiferous; cerioid; not ‘low and very compacted’. The stems spiny, or not spiny. The plants epiphytic, or scrambling, or climbing, or lithophytic; usually producing aerial roots; branched; with cladodes (in S. wittii and seemingly in S. anthonyanus), or without cladodes. The cladodes when present, with midribs, or without midribs. The plants prostrate, or pendent. The branches usually slender, rarely flattened (S. wittii), or cylindrical, or angled (or ribbed, or winged); to 100–800 cm long; when cylindric, 0.8–5(–8) cm in diameter; when flat, 7–15 cm wide. The stems segmented; not annually articulating; ribbed and grooved, or not ribbed and grooved. The ribs or wings 2–12; when present, longitudinal. The grooves wide. The plants not conspicuously tuberculate, or conspicuously tuberculate to not conspicuously tuberculate (with rib notches interpreted as representing tubercles). The tubercles connected by the ribs; borne in longitudinal series. The areoles scarcely associated with tubercles, or not tubercle-associated; distant; borne in longitudinal series, or borne along the margins of the flattened branches; simple; hairy, or without hairs; not woolly; with bristles, or without bristles; with spines (these short, bristly, hairlike or rarely acicular), or without spines (rarely). The spines when present, paired, or clustered; 1–18; 0.1–1.5(–2) cm long; with radials and centrals differentiated (rarely), or showing little or no difference between radials and centrals. The mature stems with much reduced leaves, or leafless (?).
Flowering at night (mostly), or during the day (e.g., in Deamia). The flowers lateral; one per areole; funnelform, or salver-shaped, the perianth limb broad; sessile; usually large, or very large; (4–)12–39 cm long; fragrant, or malodorous; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; not naked; with scales; with spines, or spineless. The hypanthial tube elongate, bearing small scales and areoles with hairs, bristles or spines crowded in the region of the ovary but more distant above; not naked; with scales; with spines, or spineless. The perianth with distinct calyx and corolla, or sequentially intergrading from sepals to petals, or petaline (?); white, or yellow, or brown. The perianth segments spreading; elongate, relatively narrow, or relatively short, broad; pointed, or acuminate, or apiculate. Stamens numerous; adnate to the perianth; exserted beyond the perianth; not grouped (inserted in a broad zone in the tube and encircling the throat). Gynoecium inferior (the style elongate and exserted, with numerous stigma-lobes).
The mature fruit 6–8 cm long; globose, or ovoid, or ellipsoidal; usually red; not naked (with persistent tufts of hairs, bristles or spines); spiny, or without spines; fleshy; indehiscent. The seeds black; ovoid, or pyriform, or reniform; not encased in bony arils; with hilum and micropyle fused; with a mucilage sheath. The testa shiny; minutely spotted. Cotyledons reduced or vestigial.
Natural Distribution. Southern United States, Mexico, tropical and sub-tropical South America, West Indies.
Classification. About 28 species. Subfamily Cactoideae. Tribe Hylocereeae.
Cf. Hunt (1967).
Images. • Selenicereus setaceus (as Mediocactus), with Stenocerues griseus (as Lemaireocereus) and Leptocereus arboreus: Britton & Rose (1920). • Selenicereus grandiflorus: Britton & Rose (1920). • Hylocereus undatus, H. minutiflorus (as Wilmattea), Selenicereus grandiflorus: Britton & Rose (1920). • Selenicereus urbanianus: Britton & Rose (1920). • Selenicereus coniflorus: Britton & Rose (1920). • Selenicereus spinulosus, S. pteranthus and Weberocereus panamensis: Britton & Rose (1920). • Hylocereus trigonus and Selenicereus boeckmannii: Britton & Rose (1920).
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’.
