Ludwigia adscendens
Content
Description
Herb with prostrate or ascending stems, rooting at the nodes, with conspicuous white, erect, spindle-shaped, mucronate aerophores arising in clusters at the nodes of the floating stems and from the roots, the more or less erect stems to 60 cm;
Leaves broadly oblong-elliptical, 0.4-7 by 0.7-4 cm, narrowly cuneate at base, apex acute or obtuse;
Flowers in upper leaf axils.
Sepals 5, deltoid-acuminate, 5-11 by 2-3.2 mm, glabrous or villous.
Petals creamy white, yellow at base, obovate, rounded at apex, 9-18 by 6-10 mm.
Stamens 10, epipetalous ones slightly shorter;
Capsule glabrous or villous, 1.2-2.7 cm by 3-4 mm, light brown, with 10 conspicuous darker brown ribs, terete, the seeds evident between the ribs as bumps c. 1.5 mm apart;
Seeds uniseriate in each cell of the capsule, pale brown, 1.1-1.3 mm long, ± vertical, firmly embedded in coherent cubes of woody endocarp 1.2-1.5 mm high, 1-1.2 mm thick, the endocarp firmly fused to the capsule wall.
Distribution
Asia-Tropical, Australasia, Ceylon present, S. China present, W. Arnhem Land present, continental Asia present
Continental Asia (from Ceylon to S. China), throughout Malesia, in Australia one locality in W. Arnhem Land. .
Ecology
BACKER () depicted and described in detail the biology. The root system consists of three kinds, long ± unbranched anchor roots, shorter much-branched feeding roots, and the erect spongy aerophores. BACKER cut the latter, but the plant remained (only very slightly less) buoyant. After pollination the pedicel bends down and the fruit ripens in the water (as in several other aquatics); the fruit decays and releases the cork-winged seeds which are buoyant.
On desiccated muddy soils a never-flowering terrestrial form often occurs, marked by very small crowded leaves and a stronger pubescence.
Uses
Malays in Perak use it for poulticing in skin complaints (). Batak people use this (and other aquatics, like also do the Chinese) to feed pigs, and it is recorded to be eaten as salad in Indo-China. QUISUMBING () reported that it is used in a decoction as an astringent for dysentery.
Notes
L. adscendens appears to be allied more closely to the American L. helminthorrhiza (MART.) HARA than to any Old World species. Together with the mostly yellow-flowered African L. stolonifera (GUILL. & PERR.) RAVEN, these three are the only species that regularly produce clusters of erect inflated aerophores at the floating nodes, although other species have descending root-like aerophores at these nodes and may have long, spongy aerophores from the submerged underground parts.
Citation
F.v.M. 1876 – In: Descr. Not. Pap. Pl.: 60
HOCHR. 1925 – In: Candollea: 479
RAVEN 1963: p. 387. – In: Reinwardtia: maps 31, 33
GAGN. 1925 – In: Fl. Gen. I.-C.: 987
Clarke 1879 – In: Fl. Br. Ind.: 587
HENTY & PRITCHARD 1973: p. 130. – In: Bot. Div. Lae, Bot. Bull.: fig.
TRIMEN 1894 – In: Fl. Ceyl.: 233
Koord. 1912 – In: Exk. Fl. Java: 703
ASTON 1973: Aquat. Pl. Austr.: 142
BACK. 1914: 56, 60. – In: Trop. Natuur: f. 1-5
STEEN. 1932: Arch. Hydrobiol: 314: f. 62
A. & R. FERNANDES 1957 – In: Garcia de Orta: 475
BACK. & BAKH.F. 1963 – In: Fl. Java: 260
HARTSEMA 1927: p. 242. – In: Flora (Allg. Bot. Z). n.s.: t. 3
O.K. 1891 – In: Rev. Gen. Pl.: 251
BACK. 1930: Onkr. Suiker: 469: Atlas t. 443
LINNE 1949: Fl. Sch. Indon.: 305
Ridl. 1922 – In: Fl. Mal. Pen.: 827