Description: Small annual or perennial succulent herbs or subshrubs, often with a tuberous or thickened taproot, occasionally rooting at the nodes, glabrous apart from axillary hairs in Anacampseros and Portulaca.
Leaves alternate or opposite, sometimes in basal rosettes, simple, mostly sessile, entire; stipules absent.
Inflorescences few- to many-flowered cymes, cymose panicles or terminal heads; bracts leafy or scarious. Flowers usually actinomorphic, bisexual. Sepals 2, free or fused at the base. Petals 4–11, usually 5, free or fused at the base. Stamens 3–numerous, filaments often fused at base; anthers 2-locular, dehiscing longitudinally. Ovary superior or half-inferior, 1-locular; ovules 1–numerous, placentation basal or free-central; style with 3–7 stigmatic arms or stigmas free to the base.
Fruit a capsule, 3- or 4-valved or with a circumsciss operculum; seeds 1–numerous, smooth to variously patterned.
Distribution and occurrence: World: c. 20 genera, c. 250 species, cosmopolitan. Australia: 6 genera, c. 70 species, all States.
Angiosperm Phylogeny Website (Family: Portulacaceae, Order: Caryophyllales)
Text by J. G. West
| ||Key to the genera|| |
|1||Ovary inferior or half-inferior; capsule circumsciss; flowers sessile, in terminal heads (except for Portulaca bicolor)||Portulaca|
|Ovary superior; capsule valvate or with a terminal pore; flowers pedicellate||2|
|2||Capsule separating into an epicarp that falls early and a persistent endocarp with intervalvular bristles||3|
|Capsule with united pericarp|
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|3||Leaves with axillary hairs; stamens 8–10||Anacampseros|
|Leaves lacking axillary hairs; stamens 10–20|
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|4||Leaves usually sessile, rarely petiolate, never dilated at the base, not stem-clasping; petals free||Calandrinia|
|Leaves with dilated membranous or scarious base, stem-clasping; petals united at the base|
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|5||Plants erect with ascending stems; leaves opposite; petals unequal, the basal tube split on one side||Montia|
|Plants prostrate with rhizomatous stems; leaves alternate; petals equal, basal tube complete|
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