| | The genera of Cactaceae |
~ ?Cephalocereus, Hunt (1967)
The plants cerioid; not ‘low and very compacted’. The stems spiny; globose to ovoid (at first, then becoming bottle-shaped), or shortly cylindric to elongate cylindric (when mature); cephaliate, or pseudocephaliate (initially apically, cephalium becoming ringlike and alternating with vegetative growth in S. leucostele, apical in S. luetzelburgii). The plants branched (occasionally branching basally), or unbranched; erect; shrubby, or tree-like; to 1–5 m high. The stems at least ultimately columnar. The main stem more or less cylindrical. The branches cylindrical. The stems unequally segmented, or not segmented; ribbed and grooved. The ribs 12–20; longitudinal; low. The plants not conspicuously tuberculate. The areoles not tubercle-associated; distant to closely approximating; borne in longitudinal series; simple. The flowering areoles differing in form from the non-flowering ones (being densely long-hairier and bristly). The areoles very white-; with spines. The spines clustered; 15–25; 0.5–4 cm long; with radials and centrals differentiated (the stout, white to golden centrals 3–4 cm long, the 15–20 radials 0.5–1.5 cm long). Central spines 1–5. Radial spines 15–20. The spines straight. The mature stems leafless.
The flowers lateral, or terminal and lateral (sometimes borne in older cephalia, as well as clustered in the apical one); one per areole; tubular, or funnelform, or campanulate; sessile; medium-sized to large; 2.6–7 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The pericarpel with a scattering of small scales, the areoles naked or with some white wool. The hypanthial tube ornamented like the pericarpel; not naked; with scales (small, scattered). The axils of the scales of the hypanthial tube more or less naked, or not naked (then woolly). The hypanthial tube spineless. The perianth slightly pink, or white. The perianth segments parts short, spreading.
The mature fruit 2.5–5 cm long; ovoid to ellipsoidal; purplish green, or blue; naked; without spines; with persistent floral remains (these blackening); fleshy, or non-fleshy when mature (?); indehiscent. The seeds large; black; obliquely ovoid, or pyriform; not encased in bony arils; with hilum and micropyle conjunct. The testa tuberculate. Cotyledons reduced or vestigial.
Natural Distribution. Brazil.
Classification. 2 species. Subfamily Cactoideae. Tribe Cereeae.
Images. • Stephanocereus leucostele (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’.
