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| The genera of Cactaceae |
The plants succulent; cerioid. The stems spiny, or not spiny (rarely); elongate cylindric. The plants not producing aerial roots; branched; erect; shrubby to tree-like; commonly clustering; to (2–)4–10(–12) m high. The stems columnar. The main stem more or less cylindrical. The branches cylindrical, or cylindrical and angled. The stems segmented; annually articulating (more or less); ribbed and grooved (or winged). The ribs 3–16; longitudinal; strongly developed sometimes as wings. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; closely approximating to distant; borne in longitudinal series (along the ribs); large, simple; with spines (usually, these stout), or without spines. The spines when present, clustered; 5–30; 0.4–10(–12) cm long; variously with radials and centrals differentiated, or showing little or no difference between radials and centrals. Central spines when detectable, 1–8. Radial spines 6–25. The mature stems leafless.
Flowering at night. The flowers lateral; narrowly funnelform, or tubular; sessile; medium-sized to large; 4–10 cm long; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium; not naked; without scales; with spines, or spineless. The pericarpel with numerous densely felted and often spiny areoles. The hypanthial tube bearing fewer of the densely felted and often spiny areoles than the pericarpel; without scales; with spines, or spineless. The perianth exposed during bud development; green, or red (rarely). The perianth segments short, more or less more or less erect to spreading; relatively short, broad. Stamens adnate to the perianth (inserted in the throat and upper part of the tube); not exserted.
The mature fruit (2–)4–15 cm long; globose to ovoid; green, or red; naked to not naked; spiny, or without spines (then the spines deciduous); with persistent floral remains; fleshy; with white, fleshy pulp, indehiscent. The seeds "large", with basal hilum, black; sub- reniform; not encased in bony arils; with hilum and micropyle conjunct. The testa verrucose and rugose. Cotyledons reduced or vestigial.
Natural Distribution. Ecuador, Peru.
Classification. About, 11 species. Subfamily Cactoideae. Tribe Browningieae.
Cf. Hunt, 1967.
Images. • Armatocereus riomajensis: © Zoya Akulova (2017). • Armatocereus laetus (as Laemaireocereus): 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’.
