Trianthema portulacastrum L.

Trianthema portulacastrum L.

Family

Aizoaceae

Synonyms

Trianthema monogyna L.

Vernacular Names

English

Horse purslane, carpet weed, giant pigweed.

Indonesia

Krokot, telekan (Java), krajep (Madu­ra).

Philippines

Toston (Tagalog), ngatug (Ilokano), ayam (Bisaya).

Cambodia

Chonkuëng' praëhs.

Thailand

Phakbia hin, phakkhom hin (Central).

Vietnam

C[or] tam kh[oo]i, d[af]n d[af]n.

Papua New Guinea

Pih-suh.

French

Pourpier courant

Geographical Distributions

Trianthema por­tulacastrum is distributed throughout the tropics. It is found in Peninsular Malaysia, the Philippines, Java, Madura, Lesser Sunda Islands, the Moluccas, and Papua New Guinea.

Description

T. portulacastrum is an annual, succulent, prostrate or ascending herb, up to about 60 cm tall, often much branched, smooth or finely hairy and with a firm taproot. The branches are in the axil of the smaller leaf of the leaf pair. They are alternate.

The leaves are arranged opposite, ovate-obovate to obcordate-oblong, and measure 1-5 cm x 0.5-­4.5 cm, where those of the same pair are very unequal in size. The margin is entire, purple or green. The petiole is 4-30 mm long, dilated and with sheath at the base. The pairwise connate into a funnel-shaped sheath. The stipules are small with one on each side of the petiole.

The inflorescence is a single flower in the leaf axils where the lower part is hid­den by the pouch. The flowers are bisexual and actinomor­phous. The sepals (perianth) are 5-lobed with the tube fused with the petiolar sheath, with 2 pointed bracteoles, and even with the stem. The obtuse lobes are with a long dorsal, subapical mucro, pale pink and rarely white. The petals are absent. There are 10-25 stamens, with white filaments and hairless. The ovary is superior, turbinate, truncate, with style 1.3 mm long and unilaterally stigmatose through­out its length.

The fruit is a capsule, measures 5 mm x 3 mm, part­ly exserted from the persistent perianth, truncate at apex, bilobed, with fleshy operculum, indehiscent and the basal part of capsule is thin-walled. There are 2-8 seeds, which are kidney-shaped, 1.5-2.5 mm long, with faint wavy ribs and black. The seedling is with epigeal germination.

Ecology / Cultivation

T. portulacastrum is a common weed in fields and in open, sunny localities such as roadsides, and often found on clayey soils near the sea, up to 200 m altitude. It is an aggressive weed, es­pecially in Thailand, Australia and South Ameri­ca, and can be controlled either by uprooting the plants before flowering, or by spraying the herbi­cide Fernoxone.

Line Drawing / Photograph

Trianthema_portulacastrum

References

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