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| The genera of Cactaceae |
~ Cephalocereus, cf. Hunt (1967)
Including Pseudomitrocereus Bravo & Buxb., Rooksbya Backeb.
The plants succulent; cerioid; not ‘low and very compacted’. The stems very spiny; elongate cylindric; 30 cm in diameter; pseudocephaliate, or neither cephaliate nor pseudocephaliate. The plants branched (usually), or unbranched (N. euphorbioides); erect; tree-like; with well formed trunks (these usually well developed), or not developing conspicuous trunks; solitary; to 7–15 m high. The stems columnar. The branches resembling the main stem. The main stem or trunk more or less cylindrical. The branches cylindrical. The stems not segmented; ribbed and grooved. The ribs 8–31; longitudinal; low. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; closely approximating; borne in longitudinal series; simple. The flowering areoles resembling the non-flowering ones. The areoles with spines. The spines clustered (similar in all areoles, or more abundant in the flowering region); 6–15; 0.5–5 cm long; with radials and centrals differentiated, or showing little or no difference between radials and centrals. Central spines when differentiated, (0–)1–4. Radial spines 3–13. The mature stems leafless.
Flowering at night. The flowers lateral (towards the stem tips); one per areole; cylindrical to campanulate; sessile; small; 1.2–6(–8) cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; not naked; with scales; spineless. The pericarpel with numerous fairly large tubercles and small scales naked or with a few bristles in their axils. The hypanthial tube ornamented like the pericarpel; not naked; with numerous fairly large tubercles and with scales. The axils of the scales of the hypanthial tube not naked (with a few bristles), or more or less naked. The hypanthial tube spineless. The perianth white, or yellow, or red, or pink, or purple. Stamens numerous; adnate to the perianth (inserted in the tube and throat).
The mature fruit 2–6 cm long; ovoid; not naked; spiny; with persistent floral remains; non-fleshy when mature; dehiscent (by vertical slits). The seeds light or dark brown; not encased in bony arils. The testa shiny; finely sculpted. Cotyledons reduced or vestigial.
Natural Distribution. Eastern and southern Mexico.
Classification. 9 species. Subfamily Cactoideae. Tribe Pachycereeae.
Images. • Neobuxbaumia polylopha: © Zoya Akulova (2016). • Neobuxbaumia euphorbioides: en.wikipedia.org.
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’.
