| | The genera of Cactaceae |
~ Opuntia
The plants opuntioid; not ‘low and very compacted’. The stems spiny. The plants terrestrial and self supporting, or geophytic (almost); branched (often forming cushions, looking like small clusters of platyopuntias); with cladodes to without cladodes. The cladodes when present, without midribs. The plants low growing, prostrate to erect; clustering. The branches (segments) more or less flattened, or globose, or angled; to (1–)2.5–8 cm long. The stems segmented; not ribbed and grooved. The plants more or less conspicuously tuberculate to not conspicuously tuberculate. The tubercles not connected by ribs; spirally disposed, or spirally disposed and borne along the margins of the flattened branches, or scattered. The areoles associated with tubercles to not tubercle-associated; distant (1–2 cm apart); spirally disposed, or spirally disposed and borne along the margins of the flattened branches, or spirally disposed and scattered on the surfaces; simple. The flowering areoles resembling the non-flowering ones (?). The areoles white to brown; with glochids; with spines, or without spines (T. silvestris only). The spines paired to clustered; (0–)2–12 (or more? - "usually numerous"); showing little or no difference between radials and centrals; from less than 1 cm to 7 cm long,very variable in morphological details, only sometimes acicular; straight, or curved (often bent backwards). The mature stems with well developed leaves, or with much reduced leaves, or leafless (? - oh, dear).
Flowering during the day. The flowers solitary; lateral; one per areole; sessile; medium-sized; 4–6 cm long (long, where recorded ...); regular. The receptacle conspicuously produced beyond the ovary into a tubular hypanthium to not produced beyond the ovary (?); not naked; with scales (?!); with spines, or spineless. The pericarpel spiny or bristly, sometimes tuberculate. The perianth white, or yellow, or red, or violet. Stamens not exserted. The funicles not circinate.
The mature fruit thin walled, fleshy; dehiscent; dehiscing vertically by one slit. The seeds 2.5–4.5 mm long; having the funicular envelope soft and "almost glabrous"; irregularly pyriform; laterally compressed; with perisperm to with little or no perisperm (‘reduced’); not encased in bony arils (the funicular envelope soft). The testa rugose. Cotyledons fleshy, foliaceous.
Natural Distribution. Southern Peru, Bolivia, Chile, northwestern Argentina.
Classification. 9 species. Subfamily Opuntioideae. Tribe Opuntieae.
Only very poor descriptions seen ....
Images. • Tunilla airompoa: © Zoya Akulova (2007). • Tunilla soehrensii (as Opuntia) and cf. T. corrugata (as ‘Opuntia microdisca): 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’.
