Cactaceae Juss.

Cactaceae, M. L. Gonçalves. Flora Zambesiaca 4. 1978

Morphology General Habit

Succulent perennials with stems of varied shape and bristles arising from complex axillary structures (areoles)

Morphology Reproductive morphology Flowers

Flowers solitary on areoles, sessile (except in Pereskia), bisexual, usually actinomorphic; perianth segments ? (5–13 in species of FZ area), imbricate in bud, with gradual transition between sepals and petals, fused below to form a tube (hypanthium)

Morphology Reproductive morphology Flowers Androecium

Stamens ?, inserted at base of perianth; anthers 2-thecous, splitting longitudinally

Morphology Reproductive morphology Flowers Gynoecium

Carpels 3–?, syncarpous; ovary inferior, unilocular with 3–? parietal placentas; ovules ?; style single with 3–? stigmatic lobes

Morphology Reproductive morphology Fruits

Fruit a berry

Morphology Reproductive morphology Seeds

Seeds ?

Timothy Utteridge & Gemma Bramley (2020). The Kew Tropical Plant Families Identification Handbook, Second Edition. Kew Publishing Royal Botanic Gardens, Kew

Note

Succulent plants, stem green. Leaves alternate or absent, areoles giving origin to spines, leaves and flowers. Flowers large, showy, with many series of spiralled perianth segments; ovary inferior. Fruit a many-seeded berry.

Recognition

Characters of similar families: Euphorbiaceae: latex, areoles absent, ovary superior. Crassulaceae: succulent leaves, areoles absent, ovary superior. Portulacaceae: succulent leaves, areoles absent. Aizoaceae: succulent leaves, areoles absent.

Morphology General Habit

Shrubs, trees, lianas or epiphytes; stem often succulent and green, with areoles capable of originating spines, hairs, leaves, other branches and flowers

Morphology Leaves Stipules

Stipules absent

Morphology Leaves

Leaves alternate, often missing or scale-like

Morphology Reproductive morphology Inflorescences

Inflorescences cymose or flowers more often solitary or inserted in modified stems known as cephalia

Morphology Reproductive morphology Flowers

Flowers usually actinomorphic, rarely zygomorphic; perianth segments (calyx and corolla) (6–)10–20+, spiralled, showy, transition between petaloid and sepaloid segments unclear, generally fused to a flower tube; stamens 10–50+, fused to the interior of the flower-tube; ovary inferior, manycarpellar but unilocular, placentation parietal; styles long, crowned by (3–)5–20+ stigma lobes

Morphology Reproductive morphology Fruits

Fruit berry-like (baccaceous), dehiscent or not, often coloured, with inner pulp formed by development of the funiculi, many seeded

Morphology Reproductive morphology Seeds

Seeds non-endospermic, embryo curved, often shellshaped, testa hard, white cartilaginous (Opuntioideae) or shiny and ornamented (Cactoideae, Pereskoideae).

Distribution

Almost completely New World family with 139 genera and over 1,800 species with three centres of diversity: Mexico, the Andes of Bolivia and Argentina and eastern Brazil. Large genera: Opuntia, Echinopsis, Pilosocereus, Mammillaria, Rhipsalis and Parodia. Rhipsalis baccifera also occurs in the Old World.

Ecology

Mostly in drylands.

Description Author

Daniela Zappi

Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://creativecommons.org/licenses/by/3.0

Morphology General Habit

Trees, shrubs or herbs, sometimes epiphytes, with three distinct types of branch: normal vegetative branches, areoles (reduced branches that can originate stems, spines or flowering branches) and flowering branches

Morphology Leaves

Developed leaves present in one subfamily (Pereskioideae), reduced leaves present in Opuntioideae, Cactoideae devoid of leaves

Morphology Branches

Branches green, photosynthetic, succulent, ribs and tubercles present

Morphology General Spines

Spines organized within areoles, together with hairs and bristles, specialized serrated spines and glochid present only in Opuntioideae

Morphology Reproductive morphology Flowers

Flowers generally showy, epigynous, with receptacular inferior ovary, solitary or in inflorescences, externally with areoles, bracts and many perianth segments arranged spirally and showing a transition between sepaloid (external) and petaloid (internal) segments, flower tube generally developed, nectar chamber above the ovary and basal region of the tube, stamens numerous, filaments fleshy; ovary unilocular, originated from the fusion of many carpels (generally number of carpels reflected in the number of stigma lobes)

Morphology Reproductive morphology Fruits

Fruits berry -like, fleshy, multi-seeded, indehiscent or dehiscent, seeds cochleariform, with bone-like testa in Opuntioideae, testa dark and normally shiny in Pereskoideae and Cactoideae.

Diagnostic

Cereus Mill.: Tree-like with naked large nocturnal flowers and fruits dehiscent by longitudinal slits, 30+ species mostly S. American. Pilosocereus Byles & G.D.Rowley: Shrubby to tree-like with nocturnal, dull, smelly flowers and fruits subglobose dehiscent by irregular slits, 30+ speices mostly S. American. Melocactus (L.) Link & Otto: Globose, with cephalium and small diurnal red, pink or magenta flowers, fruits white to deep red, 30+ species South American and Caribbean.  Epiphyllum Haw.: Foliose, epiphytic with showy, large flowers, 15+ species mostly Caribbean.    Rhipsalis Gaertn.: Epiphytic, string-like, with small white flowers without tube and fleshy fruits, 30+ species, mostly Brazilian Atlantic forest.    Mammillaria Haw.: Small globose to cylindric, with tubercles and two different types of areoles, latex sometimes present, small flowers appearing in rings around the stem, 50+ species mostly Mexican.  Echinopsis Zucc.: Variable habit from tree-like to globose, large flowers white to deep red, externally with areoles and hairs, 50+ species mostly Andean.   Parodia Speg.: Globose to cylindric, flowers diurnal yellow to red or pink, short tube. Opuntia Mill.: Shrubs to tree-like plants with reduced, scale-like leaves and flattened pads with glochids and serrate spines, flower with well defined green pericarpel, no tube, sensitive stamens, c. 200+ species mostly Caribbean and North American. Pereskia Mill.: Trees or climbers with well developed leaves, flowers without developed tube, white, orange, pink or red, fruits indehiscent with large seeds, c. 18 species South American and Caribbean. Distinguishing characters (always present): Presence of three types of branches: vegetative expanded branches, reduced structure bearing branches called areoles (specific to the family), flowering branches. Receptacular inferior ovary. Spines (sometimes lacking or profoundly modified). First subdivide in Subfamilies: Opuntioideae have bony seeds, serrated spines and glochids. Pereskoideae have really well developed leaves and are not very succulent. Cactoideae are stem succulents without leaves, with black shiny seeds. Useful characters to define tribes/genera: With or without conspicuous areoles. Presence/absence of ribs. Flowering structure (cephalium). Fruits (aspect, dehiscence). Seed characters. Succulence. Spines. Many perianth transitional segments (sepals and petals). Key differences from similar families: Rarely present latex (different from succulentEuphorbiaceae). Spines are produced in areoles (different from other stem succulents like Asclepiadaceae, Euphorbiaceae, etc.).

Distribution

Cultivated under glass in temperate regions, naturalised outdoors in the Paleotropics (in Australia some Opuntia became weeds), especially Opuntia ficus-indica Mill. (from Mexico but widely cultivated and introduced in Mediterranean regions, nowadays part of the culture in Europe); endemic species are endangered through habitat destruction and modification (agriculture, irrigation) and, to a lesser scale, by overcollection by amateurs. Neotropical distribution with the exception of one species, Rhipsalis baccifera (J.S.Mill.) Stearn, distributed in the Old World.

Note

The three main centres of diversity of this largely Neotropical family are the highly endemic drylands of Mexico, the Argentinian/Bolivian Andes and Eastern Brazil. A large proportion of the species are endemic to deserts and arid regions, but there are also epiphytes in the wettest forests of the Neotropics. The taxonomy of this family has been shaped by the important contribution of amateurs, who discovered and described a large number of species, many of them in cultivation nowadays. Notes on delimitation: DNA studies show that Portulacaceae possibly cannot be separated from Cactaceae because it lacks autoapomorphies; Cactaceae however presents areoles which are not present as such in Portulacaceae. Number of genera: 124 genera, over 1,300 species.

Cactaceae, R. Hunt. Flora of Tropical East Africa. 1968

Morphology General Habit

Highly specialized fleshy perennials of diverse habit

Morphology Stem

Stems terete, globular, flattened or fluted, mostly leafless and variously spiny; spines always arising from complex axillary structures (areoles)

Morphology Reproductive morphology Flowers

Flowers solitary or rarely clustered, sessile (except in Pereskia), almost always bisexual, usually regular

Morphology Reproductive morphology Flowers Perianth

Perianth segments ?, closely imbricated in bud, in a sepaloid to petaloid series, ± free or fused below to form a short or elongate tube (hypanthium)

Morphology Reproductive morphology Flowers Androecium

Stamens ?; filaments variously inserted on or at base of perianth; anthers 2-thecous, splitting longitudinally

Morphology Reproductive morphology Flowers Gynoecium

Ovary almost always inferior, with 3–? parietal placentas; ovules ?; style single; stigma-lobes 3–?

Morphology Reproductive morphology Fruits

Fruit a dry or juicy berry, often spiny, bristly or scaly

Morphology Reproductive morphology Seeds

Seeds ?, variously arillate or carunculate, with or without endosperm; embryo straight or curved

Distribution

A large, almost exclusively American family, several of whose members are grown as ornamentals in East Africa. The epiphytic genus >i>Rhipsalis is sometimes considered to be indigenous in Africa, and a number of >i>Opuntia species have become widely naturalized

Cactaceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit

Succulent herbs and shrubs of diverse habit, often very spiny, and usually with much reduced leaves

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, actinomorphic, often handsome, but very small in the African species (Rhipsalis)

Morphology Reproductive morphology Flowers Calyx

Calyx-tube adnate to the ovary and often produced beyond; lobes few to many, or reduced to minute teeth

Morphology Reproductive morphology Flowers Corolla

Petals 6 or more

Morphology Reproductive morphology Flowers Androecium

Stamens numerous, free or adnate to the base of the petals

Morphology Reproductive morphology Flowers Gynoecium

Ovary inferior, 1-celled, with parietal many- or rarely few-ovuled placentas; stigma usually radiate

Morphology Reproductive morphology Fruits

Fruit baccate, many-seeded

Morphology Reproductive morphology Seeds

Seeds mostly without endosperm

Gemma Bramley, Anna Trias-Blasi & Richard Wilford (2023). The Kew Temperate Plant Families Identification Handbook. Kew Publishing Royal Botanic Gardens, Kew

Recognition

Characters of similar families: Euphorbiaceae: stems lacking areoles, with milky latex, flowers apetalous, 3-carpellate, ovary superior, fruits explosively dehiscent. Apocynaceae (Asclepiadoideae): stems lacking areoles, with latex, flowers 5-merous, seeds with hair tufts. Didiereaceae: with seasonally borne leaves, stem areoles when present not felted, flowers 4–5-merous. Asteraceae (Kleinia): stems lacking areoles and spines, flowers in capitula, seeds (fruit) with hair tufts. Usually spiny stem succulents, rarely with fleshy leaves when in growth (Pereskia, Leuenbergeria, Quiabentia, Pereskiopsis, Austrocylindropuntia and Maihuenia).

Morphology General Habit

Tree- or shrub-like, columnar (unbranched), globose and solitary or caespitose, semi- or quite geophytic, or epiphytic and either climbing or pendent and emitting aerial roots

Morphology Stem

Stems terete, triangular or flattened, smooth, ribbed or tuberculate, growth indeterminate, or determinate and segmented, bearing felted areoles (at least when juvenile), these originating spines, barbed glochids (Opuntioideae), hair-spines, branches and flowers

Note

Some genera almost or completely spineless at maturity (Rhipsalideae, Ariocarpus, Lophophora, some Astrophytum, Copiapoa and Eriosyce) Usually spiny stem succulents, rarely leafy. Stems terete, ribbed or tuberculate, bearing felted areoles, these originating branches and flowers. Flowers ± sunken into the receptacle (pericarpel). Fruit berry-like, spiny or naked.

Morphology Reproductive morphology Inflorescences

A pseudo-inflorescence, either lateral or terminal, composed of bristles and wool, is present in a few genera

Morphology Reproductive morphology Flowers

Flower ± sunken into the receptacle (pericarpel), the latter naked, scaly, areolate-spiny, felted or with hair-spines, often tubular

Morphology Reproductive morphology Flowers Perianth

Perianth undifferentiated into sepals and petals, the segments usually very numerous (10+), variously coloured or white (rarely bluish-tinged), stamens and stigma-lobes 5–∞

Morphology Reproductive morphology Fruits

Fruit berry-like, spiny or naked, dehiscent or not, usually with fleshy funicular pulp, rarely dry

Morphology Reproductive morphology Seeds

Seeds usually many, mostly 0.5–3 mm, sometimes arillate, in Opuntioideae the bony aril encloses the entire seed.

Distribution

130 genera and 1,500 species; largely in the Americas (0–4,800 m), but Rhipsalis baccifera in Africa, Madagascar, Seychelles and Sri Lanka. Large genera are Opuntia (150+ species), Mammillaria (150+ species), Echinopsis (sensu lato, 100+ species), Parodia (50+ species), Echinocereus (50+ species) and Selenicereus (40+ species).

Description Author

Nigel P. Taylor

Use

Some larger-growing genera have edible fruit with high vitamin C content: Opuntia, Selenicereus (Hylocereus) and Cereus.