1. Aizoaceae Martinov

    1. This family is accepted.

[FTEA]

Aïzoaceae, C. Jeffrey. Flora of Tropical East Africa. 1961

Habit
Succulent or subsucculent annual or perennial herbs or subshrubs, less often shrubs
Leaves
Leaves simple, alternate, opposite or verticillate, sometimes crowded, often with an expanded membranous base, exstipulate or with membranous stipules
Inflorescences
Inflorescences cymose, loosely dichasial to umbelliform or glomerulate (flowers sometimes solitary), axillary or terminal
Flowers
Flowers regular, hermaphrodite, rarely unisexual
Calyx
Calyx of 5, less often 4 or 3, members, polysepalous or gamosepalous, usually herbaceous and persistent
Corolla
Petals absent
Sterile Parts
Staminodes sometimes present, then often petaloid
Androecium
Stamens 5-many, hypogynous or episepalous, sometimes fascicled, when definite alternate with the calyx-lobes
Gynoecium
Ovary superior or inferior, of 2–5-many united (rarely free) carpels, or of 1 carpel; loculi as many as carpels; ovules one, few, or many per loculus; placentation basal, axile, apical or parietal but not free-central
Fruits
Fruits usually capsular, loculicidal or circumscissile, sometimes indehiscent, rarely mericarpic
Seeds
Seeds usually subreniform, rarely strophiolate; embryo usually curved
[FZ]

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

Habit
Annual or perennial herbs or subshrubs, mostly succulent or subsucculent, glabrous or pubescent
Leaves
Leaves simple, opposite, alternate or sometimes crowded, exstipulate, sometimes with small stipuliform lobes at base
Inflorescences
Inflorescences solitary or in groups, axillary
Flowers
Flower hermaphrodite, regular
Perianth
Perianth segments 5, united below into a tube or almost free, ± herbaceous, imbricate or valvate, persistent
Androecium
Stamens 5–?, hypogynous, sometimes in pairs or in fascicles, when definite alternate with the perianth segments
Gynoecium
Ovary superior, of 1–5 united carpels; loculi as many as carpels; ovules 1–? per loculus; placentation parietal, axile or apical
Fruits
Fruit capsular, loculicidal or circumscissile
Seeds
Seeds usually subreniform, not strophiolate; embryo usually curved
[NTK]

Taylor, N. & Zappi, D. (2009). Neotropical Aizoaceae.

Morphology
Description

Erect or decumbent annual or perennial herbs or subshrubs, very rarely woody , sometimes reduced to a single pair of leaves. Epidermis smooth or covered in papillae with the appearance of crystals (Mesembryanthemum crystallinum L. - ice-plant). Leaves almost always opposite, succulent , often cylindric and sometimes truncate (Lithops N.E.Br., Conophytum N.E.Br.), rarely with a spiny appendix at the apex (Trichodiadema Schwantes), margins entire or sometimes toothed. Flowers hermaphrodite , mostly solitary or in small cymes, pedicellate to sessile ; calyx 3-5(-8) parted , cup-shaped, green; corolla absent and replaced by (4-)5-many staminodes, sometimes very colourful and showy, often resembling Compositae; stamens 5-numerous; stigmas free , sometimes united at base, ovary superior , semi-inferior or inferior, (2-)5-many locular, locules 1-many-seeded. Fruita indehiscent berry or more often a loculicidal capsule ; seeds small to medium, cochleariform, testa cells smooth, often brown or black.

Distribution
Distribution in the Neotropics
  • An important family in South Africa (over 2,000 species), it is represented only by a few species that occur in disturbed environments, especially in the arid regions and by the seaside.
Diagnostic
Key differences from similar families
  • Unlike Cactaceae, where succulence is found on stems and leaves (which are alternate if present) in the Aizoaceae the succulence is confined to their (generally opposite) leaves.
  • Aizoaceae differs from Portulacaceae in opposite leaves and many strap-like perianth segments of staminodial origin.
  • It can be separated from the Molluginaceae because of its succulence and generally colourful and showy flowers, while Molluginaceae are not succulent and have white, small flowers.
Other important characters
  • Leaves opposite (often).
  • Flowers open at noon.
  • Capsular fruits that open when wetted.
Distinguishing characters (always present)
  • Succulence of leaves.
  • 'Corolla' of staminodial origin.
Notable genera and distinguishing features

See above

Useful tips for generic identification
  • Ovary placentation.
  • Fruit structure and dehiscence.
  • Number of staminodes.
  • Number of calyx -lobes.
  • Leaf-shape and size.
  • Habit.
General Description
Number of genera
  • Aptenia cordifolia (L.f.) Schwantes - originally from South Africa, widely cultivated as an ornamental and escaped in arid regions; creeping plants with relatively small (c. 1.5 cm long) pink flowers. 
  • Lampranthus N.E.Br. - genus with over 180 South African species, a few cultivated as ornamental in the Neotropics; perennial subshrub with showy, daisy-like flowers.
  • Mesembryanthemum crystallinum - originated in Africa and widely cultivated throughout the world; annual herbs sometimes covered with epidermic papillae resembling crystals.
  • Sesuvium portulacastrum L. - pantropical weed from coast and salt-lakes; halophytic herb with reddish stems; erectsucculentherb with small, white flowers and drupaceous, spiny fruits, leaves deltoid.
  • Tetragonia tetragonioides (Pall.) Kuntze - grown as spinach throughout the Neotropics, sometimes naturalized.
Notes on delimitation
  • The Aizoaceae is one of the succulent families placed within the Caryophyllideae, order Caryophyllales (Behnke & Mabry, 1994), presenting betalain as the main pigment of flowers and stems and specialized photosynthesis often found in xerophytes, such as CAM and C3.
  • This family has been previously subdivided into Aizoaceae, Mesembryanthemaceae and Molluginaceae (Jacobsen, 1970).
  • The present circumscription follows Bittrich & Hartmann (1988), Hartmann (1990), Behnke & Mabry (1994) and Eggli (1994) and excludes the Molluginaceae.
General notes
  • Of the several ornamental genera grown, the most notable are the succulents Lithops and Conophytum, the stone plants, which consist of a pair of truncate leaves, often with translucent 'windows' to allow sunlight in.
  • Amongst the members of Aizoaceae with showy flowers, the anthesis is determined by the presence of sunlight, with flowers opening at noon and closing after a few hours to re-open the next day, lasting a few days.
  • The staminode-formed 'corolla' has a unique anthesis method as it grows while the flower opens, with the inside of the staminodes expanding to cause the flower to open and the outside of the staminodes growing as the flower closes at the end of the period.
  • The capsular fruits of some genera open by means of special structures when wetted and close when dry, releasing the seeds gradually.
Status
  • The Aizoaceae are extremely rich in Africa, especially in South Africa. Mostly widespread genera that are introduced and naturalized in the Neotropics.
Literature
Important literature

Behnke, H.D. & Mabry, T.J. 1994 (eds.) Caryophyllales Evolution and Systematics. Springer-Verlag, Berlin, 334 p.

Bittrich, V. & Hartmann, H.E.K. 1988. The Aizoaceae - a new approach. Bot. Journ. Linn. Soc. 97: 239-254.

Eggli, U. 1994. Sukkulenten. Ulmer, Stuttgart, 336 p.

Hartmann, H.E.K. 1990. Aizoaceae in Kubitzki, K. (ed.) The Families and Genera of Vascular Plants II. Springer-Verlag, Berlin, pp. 37-69.

Jacobsen, H. 1970. Lexicon of Succulent Plants, 2nd ed. Blandford Press, Poole, Dorset, 682 p.

[FWTA]

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

Habit
Herbs or low shrubs, often fleshy
Leaves
Leaves alternate or opposite, sometimes very small, stipulate or not
Flowers
Flowers actinomorphic, usually hermaphrodite
Calyx
Calyx-tube free or adnate to the ovary; lobes 5–8, imbricate or rarely valvate, herbaceous
Corolla
Petals numerous or absent, 1— or more-seriate, inserted in the calyx-tube
Androecium
Stamens perigynous, many or few, rarely 1, free or united at the base into bundles; anthers 2-celled, small, opening lengthwise
Gynoecium
Ovary superior or inferior, 1-several-celled; ovules solitary to many, basal, apical or axile
Fruits
Fruit a capsule or nut-like and drupaceous, often clasped by the persistent calyx
[FZ]

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

Habit
Decumbent or prostrate creeping shrubs or herbs
Leaves
Leaves opposite, sessile or shortly petiolate, more or less connate below, entire, fleshy, exstipulate
Flowers
Flowers terminal or axillary, solitary or in few-flowered cymes, bisexual, actinomorphic, haplochlamydeous
Perianth
Perianth-segments 4 or 5, 2–3 often leafy and larger than others
Sterile Parts
Staminodes petaloid, ?, white or pink to purple, persistent
Androecium
Stamens ?, in several whorls, with oblong anthers
Gynoecium
Ovary inferior, 4- or 5-locular, glandular or eglandular; stigmas as many as loculi; placentation axile or parietal
Fruits
Fruit a loculicidal capsule with subwoody walls, dehiscing stellately at the apex as valves imbibe moisture
Seeds
Seeds ?
[FZ]

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

Habit
Annual or perennial herbs or subshrubs
Leaves
Leaves alternate, entire, without stipules
Flowers
Flowers solitary or fasciculate, axillary, bisexual, actinomorphic
Perianth
Perianth-segments 3–5, with the tube adnate to the ovary
Androecium
Stamens 3–?, sometimes fasciculate
Gynoecium
Ovary inferior or semi-inferior, 2–8(9)-locular with loculus 1-ovulate
Fruits
Fruit simple, dry, indehiscent, 2–8(9)-locular, pericarp winged or horned

Images

Aizoaceae Martinov appears in other Kew resources:

First published in Tekhno-Bot. Slovar 15. 1820 [3 Aug 1820] (as "Aizoonides") (1820)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Flora Zambesiaca
Flora Zambesiaca
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of West Tropical Africa
Flora of West Tropical Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
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