Invasive Alien Species

Species Name: Ludwigia octovalvis

Family Name:
Onagraceae
Synonym:
Ludwigia pubescens (L.) Hara
Jussiaea angustifolia Lamk.
J. blumeana DC
J. junghuhniana Miq.
Origin:
South America
Description:
Perennial erect herb, hairy, 75-150 cm tall. On inundated soil often forming numerous pseudo-aerophores arising from horizontal roots running just below the mud surface and are pressed upward by the water pressure, while the end flat horizontally.  Stem sharply angular; stipules very minute. Leaves scattered, entire, shortly petioled, elliptic to narrowly lanceolate, 2.5-15 x  0.33-3 cm. Flowers axillary, solitary, actinomorphic; pedicels 0.5-7 mm long; calyx tube cylindrical, ribbed, 15-20 mm long, at the base with 2 minute acute bracteoles, lobes 4, 7-11 mm long; petals 4, yellow, 9-15 mm x 8-16 mm; stamen 8, free; anthers 2 celled; ovary inferior, 4-5 =celled with numerous ovules, style slightly longer than the stamen. Fruit capsule, with 8 obtuse ribs, 3-5 x 4 mm long, purplish at maturity.
Invaded Habitat:
Damp fields and grass lands, humid cultivated lands, along water courses, lowland irrigated, rain-fed and lebak rice fields.
Distribution:
Pantropical. Throughout Indonesia.
Ecology:
Found in ever-wet regions and those with a pronounced dry season. In Java up to 1450 alt. Flowers throughout the year.
References:
  1. Backer , C. A. & R. C. Bakhuizen Van Den Brink.  1963.  Flora of Java Vol. I.  N.V. P. Noordhoff. Groningen, Netherlands. 
  2. Soerjani, M.,  A. J. G. H. Kostermans & Gembong Tjitrosoepomo (Eds.).  1987.  Weeds of Rice in Indonesia. Balai Pustaka. Jakarta.