| | The genera of Cactaceae |
~ Stenocereus
The plants cerioid; not ‘low and very compacted’. The stems spiny; elongate cylindric. The plants branched; erect; tree-like (candelabra-like); with well formed trunks (the well defined trunk more than 1 m long at maturity); solitary; to 5–15 m high. The stems columnar. The main stem not remaining dominant (the branching basal). The branches blue-green, slightly incurving, cylindrical, or angled; to 10 cm long. The stems segmented; ribbed and grooved. The ribs 5–8; borne spirally to longitudinal; triangular, with straight margins, obtuse, to 2 cm high. The grooves wide. The plants not conspicuously tuberculate. The areoles not tubercle-associated; closely approximating, or confluent (becoming confluent with age). The confluent areoles lateral. The areoles spirally disposed to borne in longitudinal series; simple; with spines. The spines clustered; 7–15; 0.5–5 cm long; with radials and centrals differentiated (the centrals to 5cm long, the radials radiating, to 1 cm). Central spines 1–4. Radial spines 6–12 (? - "to 9 or more"). The spines straight; yellowish white, darkening with age. The mature stems leafless.
Flowering at night and during the day. The flowers aggregated (clustered); terminal; more than one per areole (from areoles that flower more than once); tubular to funnelform; sessile; medium-sized (to 5 cm long); odourless; regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The pericarpel bristly, with or without felt. The hypanthial tube without bristles; not naked; with scales. The axils of the scales of the hypanthial tube not naked (with felted areoles). The hypanthial tube spineless (and no bristles). The perianth pale green to white. The perianth segments recurved; relatively short, broad.
The mature fruit 2.5–3.5 cm long; ovoid; red; naked to not naked (sometimes with a few small bristles); without spines; without persistent floral remains; dehiscent. The seeds not encased in bony arils. Cotyledons reduced or vestigial.
Natural Distribution. Mexico.
Classification. 1 species (I. dumortieri). Subfamily Cactoideae. Tribe Pachycereeae.
Images. • Isolatocereus dumortieri: © Zoya Akulova (2018).
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’.
