Invasive Alien Species

Species Name: Leersia hexandra

Family Name:
Poaceae/Gramineae
Synonym:
Leersia abyssinica A. Rich
L. capensis C. Mueller
Origin:
Tropical America
Description:
Perennial, tufted, aquatic or swampy grass with creeping rhizomes, 25-120 cm tall. Stem ascending or suberect or somewhat prostrate below, rooting at the nodes. Leaf sheaths with markedly thickened, fleshy, cuff-like base, this –part densely clothed with rough, retrorse, white hairs, shrink considerably when dry; ligule, thin, round,  4-9 mm long; blade linear, with rough margins, 3-30 x 2-12 mm. Inflorescence terminal panicle, 5-12 cm long, with zigzag slender, sub-erect or spreading branches 2-5cm long; spikelet oblong, 3-4 mm long, overlapping, flattened, asymmetrical on short stalks with short spiny bristles along the margins.  Caryopsis oblong, free between the lemma and  palea.
Invaded Habitat:
Swamps, pools, soggy grasslands, border of the ditches, lowland irrigated, rain fed and tidal rice fields.
Distribution:
It was still rare in Java in 1860, but now common and spread throughout Indonesia except Mollucas as far as known.
Ecology:
Permanently moist site, when floating, it may have branches several meter long. It can grow in drains and impede the water flow.
References:
  1. Backer , C. A. & R. C. Bakhuizen Van Den Brink.  1965.  Flora of Java  Vol. III.  N.V. P. Noordhoff. Groningen, Netherlands
  2. Barnes, D.E. and L.G. Chan.  1990.  Common Weeds of Malaysia and Their Control.  Ancom Berhad. Persiaran Selangor, 4000 Shah Alam. 
  3. Moody, K., C.E. Munror, R.T. Lubigan and E.C. Paller. 1984. Major weeds of the Philippines. Weed Science Society of the Philippines, UPLB College, Laguna, Philippines.
  4. Soerjani, M.,  A. J. G. H. Kostermans & Gembong Tjitrosoepomo (Eds.).  1987.  Weeds of Rice in Indonesia. Balai Pustaka. Jakarta