| | The genera of Cactaceae |
Including Peirescia Zucc. (orth. var.), Peireskia Steud. (orth. var.), Perescia Lem. (orth. var.), Rhodocactus (A. Berger) F.M. Knuth
The plants non-laticiferous; not succulent (or scarcely so); more or less conventionally dicotyledonous and leafy; not ‘low and very compacted’. The stems spiny. The plants terrestrial and self supporting (mostly, small trees or shrubby, usually with trunks), or scrambling (P. aculeata with scrambling stems to 10 m long); branched; shrubby, or tree-like; to 2–10 m high. The stems not segmented; not ribbed and grooved. The plants not conspicuously tuberculate. The areoles in the leaf axils, sometimes bearing leaves; large, simple; often woolly or hairy; without glochids; eventually with spines. The spines solitary to clustered; 0.5–9 cm long; showing little or no difference between radials and centrals; unequal in length, stiff (?); more or less straight, or curved; somewhat flattened, or terete; whitish, yellowish, pinkish, brownish or ‘dark’. The mature stems with well developed leaves. Leaves of mature stems small to medium-sized ((1-)5–20 cm long); fleshy to membranous; broad, more or less persistent, entire, flat. Laminae veined.
Flowering during the day. The flowers solitary, or aggregated; terminal to lateral; one per areole, or more than one per areole (then clustered or in panicles); campanulate, or rotate; sessile, or pedunculate; medium-sized to large; 2.5–5 cm long; fragrant (at least, strongly so in P. aculeata); regular to somewhat irregular. The floral irregularity involving the perianth, or involving the perianth and involving the androecium. The receptacle not produced beyond the ovary; not naked; with scales; with spines, or spineless. The pericarpel usually areolate, bearing numerous, more or less leafy, persistent scales, their axils often spiny-areolate and sometimes proliferous. The perianth with distinct calyx and corolla, or sequentially intergrading from sepals to petals, or petaline, or of ‘tepals’; 20–100 (many); white (or whitish), or cream, or orange, or red, or pink. The perianth segments relatively short, broad; blunt (mostly), or pointed, or apiculate. Stamens 20–100 (numerous); adnate to the perianth (inserted towards the base of the perianth); not exserted; not grouped. Gynoecium superior to inferior. Locules secondarily divided by ‘false septa’ (sometimes, partially), or without ‘false septa’. Placentation basal (when the ovary is superior), or parietal. The ovules in the single cavity 15–100 (numerous).
The mature fruit (0.5–)4–10 cm long; variable in shape; with persistent floral remains; solitary or clustered, the wall mostly receptacular, fleshy; indehiscent. The seeds 1.7–7.5 mm long; the micropylar end round to noselike, black; ovoid ("ovate" ..), or reniform; not encased in bony arils. The testa shiny; smooth, without ornamentation. Cotyledons foliaceous (not succulent).
General anatomy. The vessel end-walls simple.
Physiology. C3 (in leaves), or CAM (in stems).
Natural Distribution. Lowland neotropics, from southern Mexico and the Caribbean to northern Argentina and Uruguay.
Classification. About 18 species. Subfamily Pereskioideae.
Cf. Hunt (1967).
Images. • Pereskia aculeata (as P. pereskia), Pereskia sacharosa: Briton & Rose (1919). • Pereskia grandifolia, Pereskia lychnidiflora (as Pereskiopsis pititache), Pereskiopsis rotundifolia (as chapistle): Britton & Rose (1919). • Pereskia aculeata Mill.: Bot. Reg. 1928, 1837. • Pereskia grandiflora (Pfeiff), with ‘Rhipsalis’ and ‘Epiphyllum coccineum’: Le Maout and Decaisne (1873). • Pereskia grandifolia Haw. (as P. bleo), Bot. Reg. 1473 (1831).
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’.
