Invasive Alien Species

Species Name: Hymenachne acutigluma

Family Name:
Poaceae/Gramineae
Synonym:

Hymenachne amplexicaulis (non Nees) Monod
H. myceros sensu Ridley
H. pseudointerupta C. Muell.
Panicum acutigluma Steud.
P. amplexicaule Rudge

Origin:
India
Description:
A perennial, aquatic grass, erect in shallow water, in deep water with very long floating stolons which may reach 4-6m. Stem filled with white pith up to 100 cm tall. Leaf sheaths split in front   or along margins with long tubercle-based hairs; ligule membranous, 1-2.5 cm long; blade flat, linear to linear lanceolate, sub-amplexicaule base and very acute top, glossy dark green, 15-40 cm x 10-35  mm. Inflorescence terminal, spike like, narrow panicle, cylindrical, dense, 10-40 cm long, only branched at the lower half;  branches erect, pressed against the angular or ribbed axis, the lowest 1-10 cm long, the longer ones with many very short branchlets; lateral axes minutely  bristly, rough; spikelets narrowly lanceolate, sub-cylindrical, very acute, awn-less, green, 3-5.5 mm long, with one bisexual flower and 4 distinctly spaced glumes. Caryopsis ellipsoid, between the not hardened lower lemma and lower palea, 1.5 mm long
Invaded Habitat:
Pools, swamps, along drains and water courses, lebak rice fields
Distribution:
Throughout Indonesia except Nusa Tenggara as far as known.
Ecology:
Sunny, swampy sites, it can tolerate water up to 1-2 m deep, but it is better adapted to seasonal immersion than the permanent water; often abundant, but never covering vast areas up to 1 200 m altitude. It is adapted to acid soils in peat swamps having pH 4-4.8. It is tolerant of shade. It grows best in high rainfall regions.
References:
  1. Backer , C. A. & R. C. Bakhuizen Van Den Brink.  1965.  Flora of Java. N.V. P. Noordhoff. Groningen, Netherlands
  2. Mannetje L.’t and R.M. Jones (Edts.). 1992.  Plant Resources of South-East Asia No. 4.  Forages.  Prosea Foundation, Bogor, Indonesia and Pudoc-DLO, Wageningen, the Netherlands
  3. Soerjani, M.,  A. J. G. H. Kostermans & Gembong Tjitrosoepomo (Eds.).  1987.  Weeds of Rice in Indonesia. Balai Pustaka. Jakarta.