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Ludwigia hyssopifolia (G. Don) Exell

Ludwigia hyssopifolia (G. Don) Exell

Family

Onagraceae

Synonyms

Jussiaea linifolia Vahl.

Vernacular Names

Malaysia Lakum air, inai paya, maman pasir (Peninsular).
English Willow herb.
Indonesia Jukut anggereman, mainang (Sundanese), meligai (Bangka).
Philippines Pasau na hapai (Tagalog), barigaua (Bikol), manakatud (Iloko).
Thailand Tien na.
Vietnam rau m[uw][ow]ng, rau l[uws]c.

Geographical Distributions

Ludwigia hyssopifolia is distributed throughout the tropics, including Micronesia and northern Australia.

Description

L. hyssopifolia is an annual herb, which is measure 5 cm tall (dwarf) or up to measure 3 m tall, with elongate pseudo-aerophores from submerged roots while the young parts are minutely puberulent.

The leaves are lance-shaped, 1-9 cm x 0.2-3 cm, narrowly wedge-shaped base, acuminate apex, 11-17 pairs veins and with 2. With a size of measure about 5-18 mm long petiole.

The lance-shaped sepals are 4 in number, with a size of measure about  2-4 mm long and 3-veined while the petals are elliptical in shape , with a size of measuring 2-3 mm x 1-2 mm, yellow or fading orange-yellow in colour. The stamens are 8 where the filaments are measure 0.5-2 mm long, with single pollen and with a size of measure 1-1.5 mm long style.

The capsule is measuring  1.5-3 cm x 0.1-1.2 cm, subterete, enlarged in the upper part, thin-walled and subsessile.

The seeds are dimorphous. The lower seeds are uniseriate in each cell, oblong in shape, brown in colour, where each is firmly embedded in a cube of relatively hard endocarp, while the raphe is about one third of the length of the seed. The upper seeds are multiseriate, free, ovoid in shape, pale brown in colour  and with narrow raphe.

Ecology / Cultivation

L. hyssopifolia is a common weed of pools, ditches, rice fields, fallow gardens and rice fields, both on clay and sandy soils, also occurs from sea-level up to 1000 m altitude.

Line Drawing / Photograph

Ludwigia_hyssopifolia

References

  1. Plant Resources of South-East Asia No. 12 (2): Medicinal and poisonous plants.