Limosella

Linnaeus

Sp. Pl. 2: 631. 1753.

Common names: Mudwort
Etymology: Latin limosus, full of mud, and -ella, diminutive, alluding to habitat
Treatment appears in FNA Volume 17. Treatment on page 338. Mentioned on page 324, 325.

Herbs, annual [perennial], aquatic or paludal; stolons present. Stems stoloniferous, prostrate or ascending, glabrous. Leaves basal, opposite, sometimes rosulate; stipules absent; petiole present or absent; blade fleshy or not, leathery or not, margins entire. Inflorescences axillary, flowers solitary; bracts absent. Pedicels present; bracteoles present or absent. Flowers bisexual; chasmogamous flowers emergent; sepals [4]5, calyx radially or slightly bilaterally symmetric, campanulate, lobes lanceolate to triangular; petals [4]5, corolla white, pink, pale purple, or lavender, slightly bilaterally symmetric, campanulate, not saccate, abaxial lobes 3, adaxial 2; stamens 4, adnate near mouth of corolla, didynamous or equal, filaments glabrous, staminode 0; ovary 2-locular proximally, 1-locular distally, placentation free-central; stigma capitate or slightly 2-lobed. Fruits capsules, ellipsoid to globular, dehiscence septicidal. Seeds 3–200, yellow to dark brown, fusiform or cylindric, wings absent.

Distribution

nearly worldwide.

Discussion

Species 15 (2 in the flora).

Interpretations of morphological and molecular data place Limosella in Scrophulariaceae near the African genera formerly classified as Manuleae Bentham & Hooker f. (P. Kornhall and B. Bremer 2004). Limosella is in need of revision; the characters often used for identification are variable or difficult to observe.

Key

1 Corolla lobes acute; stamens attached at different levels; styles 0.2–0.4 mm; leaf blades spatulate to linear; young leaves with auriculate sheaths at bases. Limosella aquatica
1 Corolla lobes rounded; stamens attached at same level; styles 1 mm; leaf blades linear to filiform; young leaves with tapering sheaths at bases. Limosella australis