Hymenachne acutigluma (PROSEA)
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Introduction |
Hymenachne acutigluma (Steudel) Gilliland
- Protologue: Gard. Bull. Sing. 20: 314 (1964).
- Family: Gramineae
- Chromosome number: 2n= unknown
Synonyms
Panicum acutigluma Steudel (1854), Hymenachne pseudointerrupta C. Mueller (1861), H. myurus sensu Burkill, Dict.: 1234 (1966), H. amplexicaulis sensu Backer, F. Java 3: 561 (1968).
Vernacular names
- Wick grass, dal grass (En)
- Indonesia: rumput kumpai (Indonesian), jujuket (Sundanese), blem bem (Javanese)
- Malaysia: rumput kumpai
- Philippines: lagtom (Bikol)
- Thailand: ya plong
- Vietnam: bâ_ nhon.
Origin and geographic distribution
H. acutigluma is widespread in wet habitats throughout South-East Asia. It is abundant in peat swamps in southern Thailand and is also found in India, Bangladesh, Burma, Indo-China, China, Japan, Australia and Polynesia.
Uses
The foliage is used as fodder. The pith of the culms is used for making lamp wicks. Sometimes the plant becomes a troublesome weed in irrigated rice.
Properties
H. acutigluma is very palatable. Nitrogen concentrations in 6 samples from Thailand ranged from 0.8-1.7%, but concentrations of 2.5% N in whole plants and 3.6% in leaves have been recorded in Surinam. The average intake of dry matter by sheep in Thailand was 506 g/head per day.
Botany
A perennial, aquatic grass, erect in shallow water, in deep water with very long floating stolons which may reach 4-6 m; culms and stolons hollow or filled with a white spongy pith, branched and rooting at nodes to form a bunch of feathery rootlets; culms erect, up to 1 m tall. Leaf-sheath up to 9 cm long, hairy at the margins; ligule membraneous, 1-2.5 mm long; leaf-blade linear to lanceolate, 1.5-40 cm × 1-3.5 cm, shiny dark green, amplexicaul at the base, tapering towards the apex, glabrous except at the margins at the base. Inflorescence a terminal, spike-like panicle reaching 55 cm in length, branched at the base but remaining very narrow, cylindrical, 1-3.5 cm wide; number of branches varying, 1-10 cm long; spikelets narrow, long pointed but awnless, 3-5.5 mm long, with one bisexual floret (the upper one) and one neuter (the lower one), green. Caryopsis ellipsoid, up to 1.5 mm long.
A very variable species in its leaves, inflorescences and spikelets. The species has long been thought to be identical to the American H. amplexicaulis (Rudge) Nees, causing confusion in botanical literature.
New shoots grow from the old plants at the beginning of the rainy season. Very few seeds are produced in Thailand, although it sets seed during autumn in Australia. It flowers from the middle of the rainy season onwards. Cultivar "Olive" has been released in Australia.
Ecology
H. acutigluma thrives in open swamps and ditches from sea-level up to 1200 m altitude. It is adapted to acid soils in peat swamps having pH 4-4.8. It is intolerant of shade. It grows best in high rainfall regions. It can tolerate water up to 1 m deep, but is better adapted to seasonal immersion than to permanent water.
Agronomy
Propagation by rooted stolons and division of rootstocks is best. Good soil moisture is needed for its establishment; cuttings should be planted deeply in saturated soils. It is not drought-tolerant, but has been observed to recover from seedlings when flooding recommenced after extended drought periods in Australia. Topgrowth of H. acutigluma above water level can be cut several times throughout the rainy season. The tops are then carried to animals. In Thailand it is also grazed by cattle or water buffaloes when flood water recedes. In Australia it is established behind ponding banks where it tolerates deeper water than para grass ( Brachiaria mutica (Forssk.) Stapf) and is only used for grazing. In Thailand, it is estimated that a minimum yield of 24 t/ha of fresh grass can be obtained from peat swamps. It does not make a good hay as the succulent stems take a long time to dry.
Genetic resources and breeding
There is a noticeable variation within the species. It is unlikely that any substantial germplasm collections are being maintained, although small collections are held by ATFGRC (CSIRO, Australia).
Prospects
It is a good source of feed for livestock in lowland areas that are subject to lengthy periods of flooding, especially when no other quality forage is available. Research on its agronomy and nutritive value, and on selection of better cultivars, is warranted.
Literature
- Bor, N.L., 1960. The grasses of Burma, Ceylon, India and Pakistan. Pergamon Press, London. pp. 313-314.
- Manidool, C., 1989. Natural grassland and native grasses of Thailand [in Thai]. Technical Bulletin No 1301-26-32. Division of Animal Nutrition, Department of Livestock Development, Bangkok. p. 31.
- Oram, R.N., 1990. Register of Australian herbage plant cultivars. CSIRO, Australia. pp. 107-108.
- Soerjani, M., Kostermans, A.J.G.H. & Tjitrosoepomo, G., 1987. Weeds of rice in Indonesia. Balai Pustaka, Jakarta, No 3521. pp. 432-433.
Authors
C. Manidool
