Disphyma N.E.Br.

Scientific Description

Common name. Roundleaf Pigfaces. Family Aizoaceae.

Habit and leaf form. Shrubs, or herbs. ‘Normal’ plants. Leaves well developed. Plants succulent. The herbs annual. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Young stems cylindrical. Stem internodes solid. Xerophytic (commonly found on samphire flats, coastal dunes and inland saline areas). Leaves minute to medium-sized; alternate (clustered on erect short shoots, ‘indeterminate’); fleshy; imbricate to not imbricate; shortly petiolate, or subsessile; sheathing, or non-sheathing; simple; epulvinate. Leaf blades entire; solid; semi-terete (clavate and triquetrous). Leaves with stipules, or without stipules. Vegetative buds not scaly. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent (smooth or glaucous or green, often with yellow or red tinge). Urticating hairs absent. Extra-floral nectaries absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring, or anomalous; via concentric cambia.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous (diurnal).

Inflorescence and flower features. Flowers solitary (flowers on short shoots — but ‘inflorescences terminal’); pedicellate, or sessile (pedicels terete, up to 10cm long, or rarely sessile); ebracteate; ebracteolate; small, or medium-sized; regular; cyclic; pentacyclic to polycyclic. Free hypanthium present; includes the calyx, staminodes and stamens. Perianth sepaline (considered apetalous, but with colourful, conspicuous staminodal ‘petals’); 5, or 20–120 (if the staminodes are interpreted as petals). Calyx present; 5 (2 large and opposite segments, 3 smaller segments with broad membranous margins); 1 -whorled; gamosepalous; imbricate, or valvate (rarely); regular; fleshy; persistent. Corolla absent. Fertile stamens present. Androecial members indefinite in number. Androecium 50–100 (i.e. to ‘many’, by branching). Androecial members maturing centrifugally; all equal; free of one another; 4–16 -whorled (i.e to ‘many whorls’). Androecium including staminodes (staminodes petal-like, purple or white at base). Staminodes 20–50 (many); petaloid. Stamens 20–100 (many); all more or less similar in shape; polystemonous; staminodes outside stamens; filantherous. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen shed as single grains. Fertile gynoecium present. Gynoecium 5 carpelled. The pistil 5 celled. Gynoecium syncarpous; synovarious to synstylovarious; inferior. Ovary plurilocular; 5 locular. Gynoecium stylate. Styles 5. Stigmas 5. Placentation parietal. Ovules 20–50 per locule (many); anatropous, or campylotropous.

Fruit and seed features. Fruit non-fleshy; dehiscent (dehisces when wet); a capsule. Capsules loculicidal, or septicidal, or circumscissile. Fruit 5 celled; 20–100 seeded (many). Seeds non-endospermic. Perisperm present (mealy). Embryo well differentiated. Cotyledons 2. Embryo curved.

Additional comments. Prostrate with stems to 1.5m long, rooting at nodes.

Etymology. From the Greek referring to the twin nodules on the apex of the ovary.