| | The genera of Cactaceae |
~ Cephalocereus, cf. Hunt (1967)
Including Austrocephalocereus Backeb., Siccobaccatus P.J. Braun & Esteves
The plants cerioid; not ‘low and very compacted’. The stems densely spiny; cephaliate (with continuous or discontinuous, sunken or superficial, lateral, woolly and bristly cephalia). The plants basally branched, or unbranched; erect; shrubby, or tree-like; solitary; to (0.7–)1–6 m high. The stems columnar (mostly), or not columnar. The branches resembling the main stem. The main stem more or less cylindrical. The branches cylindrical. The stems not segmented; ribbed and grooved. The ribs 10–35; longitudinal; narrow. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; fairly closely approximating; borne in longitudinal series; simple. The flowering areoles differing in form from the non-flowering ones (close-set in the pseudocephalia, with long wool and spines). The areoles without glochids; with spines. The spines clustered; several to many, 8–30; 0.5–5 cm long (occasionally with longer bristles); with radials and centrals differentiated, or showing little or no difference between radials and centrals. Central spines when present, 1, or 3–10. Radial spines 4–30. The mature stems leafless.
Flowering at night and during the day. The flowers usually aggregated (clustering); lateral (but towards the stem apex); one per areole; tubular; sessile; small to medium-sized; 2–5 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The pericarpel naked save for tiny scales. The hypanthial tube not naked; with scales (these tiny). The axils of the scales of the hypanthial tube more or less naked. The hypanthial tube spineless. The perianth white, or orange, or red, or pink, or purple. The perianth segments relatively short, broad.
The mature fruit 1–7 cm long; naked; with persistent floral remains to without persistent floral remains (these shed late); fleshy; indehiscent. The seeds dark brown; not encased in bony arils; with hilum and micropyle conjunct. The testa pitted (but "nearly smooth"). Cotyledons reduced or vestigial.
Natural Distribution. Central and eastern Brazil.
Classification. 9 species. Subfamily Cactoideae. Tribe Cereeae.
Images. • Micranthocereus purpureus (as Cephalocereus): 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’.
