Ludwigia adscendens subsp. diffusa (Forssk.) P.H.Raven

Ghazanfar, S. A. & Edmondson, J. R (Eds). (2014) Flora of Iraq, Volume 5 Part 2: Lythraceae to Campanulaceae.

Morphology Stem

Stems spreading, prostrate or ascending, to at least 1 m long, rooting at the nodes, with tufts of white aerenchyma from submerged stems

Morphology Branches

Branches densely villous, more rarely glabrous

Morphology Leaves

Leaves narrowly lanceolate to narrowly elliptical, 2–9 × 0.3–2.3 cm, broader on sterile shoots

Morphology Reproductive morphology Flowers

Flowers axillary

Morphology Reproductive morphology Flowers Calyx

Sepals 5, 5–10 × 2–3.2 mm Petals 5, bright yellow, 10–18 mm long, 6–10 mm wide, entire

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, the episepalous longer

Disc

Disc elevated, densely white-hairy; style 4.5–8 mm

Morphology Reproductive morphology Fruits

Capsule 15–27 mm, dark brown, shining, on a pedicel 0.6–1.7 cm, ribbed, the seed showing clearly as a series of bumps ± 1.5 mm apart between the ribs

Morphology Reproductive morphology Seeds

Seeds approximately vertical, 1.1–1.2  mm, firmly embedded in coherent cubes of woody endocarp at maturity.

Ecology

Shallow water, wet places, moist soil; up to alt. 10 m

Phenology

Flowering and fruiting: Apr.-Oct.

Distribution

Common in southern marshes of Iraq, and also in other marshy localities. This species, widespread in the western Tropics and Subtropics of the Old World, is tetraploid (n = 16), unlike the Asian L. adscendens (Jussiaea repens) and other closely related taxa, which are diploid (n = 8). Syria, Lebanon, Palestine, Egypt, throughout Africa.

Note

Ludwigia stolonifera, kobani or gubani Ir., lsm armat (lower Ir., possibly a corruption of Ar. armadh for sea-weed, water-weed, green scum on water etc. ?).

Morphology Roots

This plant develops two kinds of roots (cf. Gillett 9964): ordinary siliceous anchorate roots and spongy aerating roots (“pneumatophores”), consisting largely of aerenchymatous tissue, which arise from the true roots or from the stems and grow upwards often until they reach the surface of the water.

Onagraceae, P. H. Raven. Flora Zambesiaca 4. 1978

Morphology General Habit

Herb with prostrate or ascending stems, rooting at the nodes, with conspicuous white erect fusiform mucronate pneumatophores arising in clusters at the nodes of the floating stems and from the roots; plants more or less densely villous to glabrous.

Morphology Leaves

Leaves 2–9 × 0·5–1·7(2·3) cm. on flowering stems, broader on floating non-flowering branches, dark green, shining, narrowly lanceolate to narrowly elliptical, narrowly cuneate at the base, the apex acute; main veins 6–12 on each side of the midrib; petioles 0·2–2 cm. long.

Morphology Reproductive morphology Flowers

Flowers borne singly in upper leaf axils.

Morphology Reproductive morphology Inflorescences Bracteoles

Bracteoles c. 1 mm. long, deltate.

Morphology Reproductive morphology Flowers Calyx

Sepals 5, 5–14× 1·5–2·8 mm., deltate acuminate.

Morphology Reproductive morphology Flowers Corolla

Petals 7–18 × 4–10 mm., lemon-yellow with a darker spot at the base, obovate, rounded at the apex.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, the epipetalous ones slightly shorter; filaments 2·5–4 mm. long; anthers 1·2–8 mm. long, extrorse and not shedding pollen on the stigma at anthesis.

Morphology Reproductive morphology Flowers Pollen

Pollen grains shed individually.

Morphology Reproductive morphology Flowers Disc

Disk slightly elevated, with a depressed white-hairy nectary surrounding the base of each epipetalous stamen.

Morphology Reproductive morphology Flowers Gynoecium Style

Style 3–8 mm. long, densely long-hairy to just below stigma; stigma 1·5–2 mm. across, 1–1·2 mm. high, golden-yellow, elevated above the anthers at anthesis, the upper receptive.

Morphology Reproductive morphology Fruits

Capsule 10–30 × 3–4 mm., glabrous or villous, light brown, with 10 conspicuous darker brown ribs, terete, the seeds evident between the ribs as bumps c. 1·5 mm. apart; capsules thick-walled, very tardily and irregularly dehiscent; pedicel 0·5–2 cm. long.

Morphology Reproductive morphology Seeds

Seeds 1·1–1·3 mm. long, uniseriate in each locule of the capsule, pale brown, more or less vertical, firmly embedded in coherent cubes of woody endocarp 1·2–1·5 × 1–1·2 mm., the endocarp firmly fused to the capsule wall.

Cytology

Chromosome number n=16.