Montiaceae

Smooth, fleshy, non-woody (herbaceous) ephemerals, above ground portions of plants often disappearing within 8 weeks of when they first appear; perennial with large round tubers (Claytonia); or annual or biennial with fibrous roots and no bulbs or tubers (Montia).

Stems erect, lying along the ground at the base and curved upward toward the tip, or sprawling on the ground; forming mats and rooting at the nodes in Montia. Stem leaves opposite, in one or sometimes more pairs, usually widest above the middle, often spoon-shaped, with no teeth along edges.

Flowers at tops of stems, or in axils; solitary, in pairs or in racemes or cymes with up to 15 flowers; often one-sided at least toward the top, supported by bracts or not. Flowers each producing both pollen and seeds; radially symmetrical. Sepals 2, persistent; leaf-like and unequal in Claytonia. Petals 5, separate or fused to one another at the base, equal or not. Stamens 3 or 5, attached to the base of the petals in Claytonia; pollen-producing structure at top (anther) pink or yellow. Carpels 3, fused to form 1 pistil; ovary located above point of attachment of other flower parts (superior); style with 3 lobes or branches. Fruit capsules, with 3 valves, splitting open from the tip to release black seeds. Seeds may or may not have fleshy, fat-and-protein-rich structures (elaiosomes) attached to them, these serving as a food reward to attract ants, which disperse the seeds.