| | The genera of Cactaceae |
~ Cephalocereus, Hunt (1967)
Including Pilocopiapoa F. Ritter
The plants condensed-cactoid; low and very compacted in their entirety. The plants’ appearance dominated by crowded interlacing areolar structures obscuring any tubercles, ribs or furrows, or dominated neither by crowded areolar structures nor by tubercles covering the areoles. The stems usually spiny, or not spiny; sometimes tap-rooted, globose (at first), or shortly cylindric (subsequently); cephaliate (with a dense development of wool at the top, in which the flowers develop), or neither cephaliate nor pseudocephaliate. The plants branched, or unbranched, or offsetting; erect; solitary (mostly, sometimes spectacularly so), or clustering; to 12 cm in diameter. The stems not segmented; ribbed and grooved. The ribs (8–)10–40; longitudinal; distinct. The grooves wide to deep and narrow. The plants more or less conspicuously tuberculate to not conspicuously tuberculate (often shallowly so, bearing the more or less spiny areoles). The tubercles connected by the ribs; borne in longitudinal series. The areoles associated with tubercles; closely approximating, or distant. The components of adjacent areoles so extensively covering the mature plant body as to obscure any ribs or furrows, or not obscuring details of the plant body. The areoles borne in longitudinal series; simple; woolly; without glochids; with spines (usually, variable), or without spines. The spines when present, solitary (rarely), or paired, or clustered; (1–)6–32; 0.2–6 cm long; with radials and centrals differentiated, or showing little or no difference between radials and centrals; straight, or curved. The mature stems leafless.
Flowering during the day. The flowers solitary; terminal (arising near the retuse, woolly stem apices); one per areole; shortly funnelform to campanulate; sessile; immersed in the apical wool; 1.5–5.5 cm long; regular. The receptacle scarcely produced beyond the ovary to not produced beyond the ovary; naked, or not naked; with scales, or without scales; spineless. The hypanthial tube naked, or not naked; with scales, or without scales; spineless. The perianth petaline, or of ‘tepals’; yellow, or yellow and red (the outer members being sometimes reddish). The perianth segments relatively short, broad; blunt, or pointed. Stamens inserted in the tube as a single series; not separated from the perianth by a ring of hairs; not grouped.
The mature fruit 0.8–1.5 cm long; globose, or turbinate; pink; naked (with only a crown of sepal-like scales); without spines; with persistent floral remains; fleshy to non-fleshy when mature (?); dehiscent; dehiscing transversely near the top ("apically"), or irregularly dehiscent (tearing). The seeds large; with large hilum, black; not encased in bony arils; with hilum and micropyle conjunct. The testa shiny. Cotyledons reduced or vestigial.
Natural Distribution. Chile. South America.
Classification. 15–20 species. Subfamily Cactoideae. Tribe Notocacteae.
Images. • Copiapoa cinerea: © Zoya Akulova (2010). • Copiapoa tenuissima: © Zoya Akulova (2014). • Copiapoa coquimbana, with Echinopsis aurea and Lophophora williamsii: Britton & Rose (1922).
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’.
