| | The genera of Cactaceae |
~ Cephalocereus, cf. Hunt (1967)
Including Pierrebraunia Esteves
The plants cerioid (sometimes tuberous-rooted); not ‘low and very compacted’. The stems spiny; shortly cylindric to elongate cylindric; cephaliate. The plants terrestrial and self supporting, or scrambling, or climbing (occasionally); little branched (basally), or unbranched; prostrate, or erect; low, shrubby; to 1.1–2 m high. The main stem more or less cylindrical. The branches slender, cylindrical (mostly), or globose. The stems segmented, or not segmented; ribbed and grooved. The ribs 7–17; longitudinal; low. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; closely approximating to distant; borne in longitudinal series (along the ribs); close-set, simple. The flowering areoles differing in form from the non-flowering ones. The areoles woolly (at first), or not woolly (later); without glochids; with spines. The spines small, clustered; 7–26; 0.4–3 cm long; with radials and centrals differentiated, or showing little or no difference between radials and centrals. Central spines when detectable, 1–8. Radial spines 6–23. The mature stems leafless.
Flowering during the day. Pollination ornithophilous. The flowers often aggregated, or solitary to aggregated; terminal; one per areole; tubular; sessile; medium-sized to large; 3–4.5 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; naked. The perianth barely expanding; variously white, or yellow, or red, or pink, or purple, or violet; limb short or none. The perianth segments relatively short, broad; blunt. Stamens and style not exserted.
The mature fruit 1–3 cm long; globose, or ovoid, or ellipsoidal, or pyriform; rose pink, or purple, or red; naked; without spines; without persistent floral remains; berry-like, smooth, fleshy (with white pulp); indehiscent. The seeds to 1.5 mm long; black; ovoid to pyriform; not encased in bony arils; with hilum and micropyle conjunct. The testa tuberculate. Cotyledons reduced or vestigial.
Natural Distribution. Eastern Brazil.
Classification. 4 species. Subfamily Cactoideae. Tribe Cereeae.
Images. • Arrojadoa rhodantha, with Cleistocactus baumannii and Hylocereus stenopterus: Britton & Rose (1920). • Arrojadoa rhodantha, with Cleistocactus alamoensis (as Borzicactus) and Stenocereus alamoensis (as Rathbunia): 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’.
