Limosella aquatica is a very inconspicuous moss-like herb that carpets areas around ponds and cattle tanks. The 1-2cm long leaves are spatulate to oblanceolate and glandular spotted. The 3mm corollas have five lobes and are white to lavender with purple anthers. There are only four stamens. The fruit is a capsule.

General: Perennial, small, tufted, often forming mats; scapose, often submerged with floating leaves; herbage glabrous; roots fibrous.

Leaves: Basal, narrowly spatulate or broadly oblong-elliptic, 1-3 cm long, 3-12 mm wide, mostly 3-veined, glabrous, margins entire; petioles long, some as long as the water is deep, the base broadly expanded into membranous stipule-like structures.

Flowers: Solitary, borne in the axils of one or both opposite leaves; pedicels 8-22 mm long, bearing 2 bractlets at the apex just below the calyx, these resembling the calyx segments; calyx segments 5, connate at the base, lanceolate, 3.2-5.5 mm long, often elongating in fruit; corolla tubular, 7-10 mm long, yellow with dark veins, pilose within, the 5-lobed limb white to pale lavender; stamens 2, included within the corolla; flowers June- August.

Fruits: Septicidal capsule, ovoid-spherical, about 3 mm long, membranous; seeds numerous, dark brown.

Ecology: Wet habitats, pond and lake margins, often in mud or submerged; 2100-3000 m (7000-10000 ft); Apache, Coconino, Graham, and Santa Cruz counties; Canada, north-central, western, and southwestern U.S.

Notes: Limosella acaulis (Owyhee mudwort) is often difficult to distinguish from L. aquatica; it has smaller, narrower leaves (6-12 mm long) that are less spoon-shaped toward the apex, longer styles, and smaller corolla lobes, but these characters are often found in typical L. aquatica. It occurs in similar habitats.

Editor: Springer et al. 2008

Lvs with an elongate, slender petiole 1.5-10+ cm and a lanceolate to elliptic blade 1-3 cm נ2.5-12 mm; cor 2.5-3.5 mm; otherwise much like no. 2 [Limosella subulata Ives]; 2n=40. Muddy shores; interruptedly circumboreal, reaching our range in w. Minn. June-Sept.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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