Bergia L.

Scientific Description

Family Elatinaceae.

Habit and leaf form. (Sub-) shrubs, or herbs. Annual, or perennial. Helophytic (favouring areas that are periodically inundated). Leaves opposite; decussate; petiolate to subsessile; simple; epulvinate. Leaf blades entire; pinnately veined; attenuate at the base. Leaves with stipules. Stipules interpetiolar; herbaceous or membranous with a membranous margin, often toothed or laciniate, often connate at the base and sometimes adnate basally to the petioles, acuminate; persistent. Leaf blade margins serrate (usually serrulate). Leaves without a persistent basal meristem. Stem anatomy. Secondary thickening absent, or developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers solitary (or paired), or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in fascicles (in dense globular clusters). The terminal inflorescence unit cymose. Inflorescences axillary. Flowers bracteate. Bracts persistent. Flowers bracteolate. Bracteoles persistent. Flowers small; regular; 3–5 merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Perianth with distinct calyx and corolla; 6–10; 2 -whorled; isomerous. Calyx 3–5; 1 -whorled; more or less polysepalous; imbricate; regular; herbaceous with a membranous laciniate margin, sometimes keeled or winged; persistent. Corolla 3–5; 1 -whorled; polypetalous; imbricate; regular; usually white, or pink; persistent. Androecium 3–5, or 6–10. Androecial members free of the perianth; all equal; free of one another; 2 -whorled, or 1 -whorled (the inner whorl sometimes aborted). Androecium exclusively of fertile stamens. Stamens 3–5, or 6–10; isomerous with the perianth, or diplostemonous; when 1-whorled oppositisepalous. Anthers ellipsoid; dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 3–5 carpelled. The pistil 3–5 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; synovarious; superior. Ovary plurilocular; 3–5 locular. The ‘odd’ carpel (when G3) anterior. Gynoecium stylate (usually), or non-stylate (the stigmas of B. pedicellaris more or less sessile). Styles 3–5; free; apical; persistent. Stigmas 3–5; capitate. Placentation axile. Ovules 15–50 per locule (i.e. ‘many’); horizontal to ascending; with lateral or superior raphe; non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules septicidal. Seeds shortly cylindric; non-endospermic. Cotyledons 2 (relatively short). Embryo straight to curved. Seedling. Germination phanerocotylar.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, South Australia, Northern Territory, Queensland, New South Wales, Victoria, and Australian Capital Territory. Northern Botanical Province and Eremaean Botanical Province.