| | The genera of Cactaceae |
The plants succulent; opuntioid; not ‘low and very compacted’. The stems spiny. The plants branched (the insertion of branches ‘more or less cruciform’); with cladodes (flattened branches). The cladodes without midribs. The plants erect; tall, tree-like (sometimes with several main stems or trunks); with well formed trunks, or not developing conspicuous trunks; to 1–10 m high. The branches differing in form from the main stem. The main stem remaining dominant; or trunk more or less cylindrical, or flattened (at least above). The branches flattened (in the vertical plane, oblong, somewhat irregular in outline but the upper margin straight and the lower one curved); flattened in the vertical plane, with the upper margin straight and the lower one curved. The stems segmented; not ribbed and grooved. The plants not conspicuously tuberculate. The areoles not tubercle-associated; distant; borne along the margins of the flattened branches and scattered on the surfaces (sometimes concentrated distally); simple; hairy; woolly; with glochids; with spines (usually), or without spines. The spines when present, solitary, or paired, or clustered; 1–9(–45); 0.8–15 cm long; showing little or no difference between radials and centrals. The mature stems with much reduced leaves, or leafless. Leaves of mature stems small; fleshy; terete.
Flowering during the day. The flowers lateral; one per areole; cup shaped, "globose"(!), or "opening widely with recurved perianth parts"; sessile; medium-sized; 1–7.5 cm long; regular. The receptacle scarcely produced beyond the ovary, or not produced beyond the ovary; not naked; with scales; with spines. The pericarpel elongate, sometimes flattened or bent, with spiny areoles. The hypanthial tube if present, not naked; with scales; with spines. The perianth rotate; yellow, or orange, or red. The perianth segments short, relatively short, broad; blunt, or pointed. The androecium without staminodes. Stamens not exserted. The funicles circinate.
The mature fruit 2–9 cm long; oblong to ellipsoidal, or ovoid; naked (?), or not naked (usually); spiny, or without spines; fleshy; indehiscent. The seeds 3–4 mm long (or in diameter ...); with the funicular girdle strongly protruding, 3–4 mm in diameter, yellowish white; conspicuously hairy (on the funicular envelope); compressed; encased in their bony arils. Cotyledons fleshy, foliaceous.
Natural Distribution. Florida, Cuba, Haiti, Jamaica.
Classification. About 8 species. Subfamily Opuntioideae. Tribe Opuntieae.
Images. • C. spinosissima (as Opuntia): Britton & Rose (1919).
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’.
