| | The genera of Cactaceae |
~ Trichocereus, cf. Hunt (1967)
Including Meyenia Backeb.
The plants succulent; cerioid; not ‘low and very compacted’. The stems spiny; neither cephaliate nor pseudocephaliate. The plants sometimes epiphytic, or terrestrial and self supporting (mostly); branched (basally or above); erect; large, shrubby to tree-like; with well formed trunks, or not developing conspicuous trunks; to 2–6 m high. The stems columnar. The main stem more or less cylindrical. The branches cylindrical; 4–15 cm in diameter. The stems not segmented; ribbed and grooved. The ribs 10–35; longitudinal; blunt. The plants ultimately conspicuously tuberculate, or conspicuously tuberculate to not conspicuously tuberculate (ultimately notched). The tubercles obtuse. The tubercles when detectable, connected by the ribs; borne in longitudinal series. The areoles associated with tubercles to not tubercle-associated; 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. The spines clustered (often stout); 15–60; 0.4–7 cm long; with radials and centrals differentiated (the centrals longer), or showing little or no difference between radials and centrals. Central spines when determinable, 1–12(–15). Radial spines 10–30. The mature stems leafless.
Flowering at night (mostly), or at night and during the day (?). The flowers lateral; one per areole; tubular to funnelform; sessile; large; 7.5–12 cm long; regular to somewhat irregular (sometimes bilaterally symmetrical). The receptacle conspicuously produced beyond the ovary into a tubular hypanthium. The pericarpel densely covered with scales and hairs. The hypanthial tube bent into an S shape; not naked; with scales (covering it). The axils of the scales of the hypanthial tube not naked (with dense wool). The hypanthial tube spineless. The perianth white, or white and pink, or red, or brown (-ish). Stamens not grouped.
The mature fruit 3–4 cm long; globose, or ovoid, or ellipsoidal, or barrel-shaped; not naked (covered with hairs); fleshy. The seeds not encased in bony arils. Cotyledons reduced or vestigial.
Natural Distribution. Northeastern Andean hinterland of southern Peru, northern Chile.
Classification. About 10 species. Subfamily Cactoideae. Tribe Trichocereeae.
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’.