| | The genera of Cactaceae |
~ Opuntia, cf. Hunt (1967)
The plants opuntioid; not ‘low and very compacted’. The stems spiny. The plants branched (the branches more or less whorled); with cladodes. The cladodes without midribs. The plants erect; tree-like; with well formed trunks; solitary; to 15–24 m high. The branches differing in form from the main stem (the intermediate segments cylindrical, the ultimate ones irregular in outline, rhomboid to ovate distally to a narrow base, producing thin, deciduous leaflike cladodes). The main stem remaining dominant; more or less cylindrical (comprising the cylindrical trunk). The branches flattened (thin); 35 cm in diameter; not combining a straight upper margin with a curved lower one. The stems segmented; not ribbed and grooved. The plants fairly conspicuously tuberculate to not conspicuously tuberculate. The tubercles not connected by ribs; spirally disposed, or scattered (?). The areoles associated with tubercles, or not tubercle-associated; borne along the margins of the flattened branches and scattered on the surfaces; simple; with glochids; with spines, or without spines. The spines when present, solitary to paired, or clustered; 1–3; to 1.5 cm long; showing little or no difference between radials and centrals. The mature stems with much reduced leaves. Leaves of mature stems minute to small.
Flowering during the day. The flowers lateral; one per areole; sessile; medium-sized to large; to 6 cm long. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium, or scarcely produced beyond the ovary, or not produced beyond the ovary (?); not naked; with scales; with spines, or spineless. The hypanthial tube not naked; with scales; with spines, or spineless (i.e., the tube and pericarpel bearing leaflike scales, and areoles with glochids and sometimes spines? - cf. Opuntia). The androecium including staminodes (these hair-like). Stamens numerous; adnate to the perianth; not exserted (?). The funicles circinate.
The mature fruit 3–4 cm long (or in diameter); variously shaped; yellow, or orange, or red, or purple; not naked (areolate); with glochids (the areoles bearing dark brown clusters of these); indehiscent. The seeds 6.5 mm long; 1–5 per fruit, with a prominent funicular girdle; conspicuously hairy (the funicular envelope woolly); compressed (disklike); with perisperm to with little or no perisperm (reduced); encased in their bony arils. Cotyledons fleshy, foliaceous.
Natural Distribution. Brazil, Paraguay, Peru, Bolivia, Argentina.
Classification. About 4 species. Subfamily Opuntioideae. Tribe Opuntieae.
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’.
