Ischaemum ciliare (PROSEA)
Ischaemum ciliare Retzius
- Protologue: Observ. bot. 6: 36 (1791).
- Family: Gramineae
- Chromosome number: 2n= 36
Ischaemum indicum auct. (non (Houtt.) Merrill, 1938), I. aristatum auct., (non L., 1753).
- Batiki blue grass, smutgrass (En)
- Indonesia: blembem (Javanese), rumput padang (Billiton)
- Malaysia: rumput gerek telinga
- Thailand: ya wai (eastern), ya-yonhu (southern).
Origin and geographic distribution
Batiki blue grass is native to South and South-East Asia. It was introduced to West Africa, southern Europe, Australia and the Pacific Islands.
It is used as forage and also as a cover grass to bind soil and reduce erosion. A dwarf form is used for lawns.
Nitrogen concentrations ranged in experiments from 2.2% at 3 weeks to 1.7% at 6 weeks, 1.3% at 8 weeks and to below 1.0% in mature forage. There have been reports that it taints milk.
A perennial, spreading or tufted stoloniferous grass rooting at the nodes, with erect or geniculate culms up to 60 cm tall, often branching and hairy at the nodes. Leaf-sheath 3-6 cm long, often tight, glabrous or sparsely hairy; ligule membranous, truncate, 1-2 mm long, entire or lacerate; leaf-blade narrowly lanceolate, up to 20 cm × 1 cm, acuminate at apex, usually sparsely to densely hairy. Inflorescence well exserted, composed of two terminal, closely opposed or somewhat divergent racemes 2-10 cm long; spikelets paired, bisexual, one sessile, one pedicelled, alternately on one side of the triangular rachis; rachis and pedicel hairy along angles; lower glume winged at apex, forming 2 large obtuse lobes; upper lemma deeply notched, excurving into a long kneed and twisted awn 8-15 mm long.
Seeds have a dormancy period and germination improves after 9-10 months storage. Seedling growth is vigorous.
It is a short-day plant, flowering throughout the year in Malaysia, in June-July in Thailand, and in July-August and January-February in India. Seed set is often poor and the grass spreads primarily by stolons.
I. ciliare is a very variable species, subdivided into 3 varieties with one variety divided into 3 subvarieties, but the whole complex needs a thorough investigation with modern experimental taxonomical methods. The species has for a long time been considered to be I. aristatum L., but this has glabrous nodes, an unlobed lower glume and only its sessile spikelets are awned. Since 1938 this species has been known as I. indicum (Houtt.) Merrill. In 1991, however, Veldkamp discovered that the basionym for I. indicum , Phleum indicum Houtt., was another species ( Polytrias indica (Houtt.) Veldk.) and consequently the correct name for this species became I. ciliare .
Batiki blue grass is an opportunistic invader of open or disturbed habitats. It is adapted to a wide range of rainfall regimes, including waterlogged areas in the wet tropics receiving over 2000 mm annual rainfall and to seasonally dry monsoonal areas of India. It has been reported as having some shade tolerance. It tolerates acid soils and soils with poor fertility, but responds to applications of fertilizer on such soils.
Batiki blue grass can readily be established from rooted cuttings and a spacing of 30 cm × 30 cm has been recommended. Establishment from seed is much slower and requires good seed-bed preparation. It is usually harvested by grazing animals, but can be cut and fed fresh or used to make hay and silage. It should be cut at booting as quality is poor if left for longer. Four cuts a year are possible.
In Malaysia flowers are often infected with a smut fungus resulting in diseased inflorescences that do not emerge from the uppermost leaf-sheaths.
Dry matter yields of Batiki blue grass have ranged from 3-20 t/ha per year depending primarily on soil fertility and fertilizer application. When grown with Stylosanthes guianensis (Aublet) Swartz in Sarawak, the mixture yielded 14.5 t/ha of DM.
Genetic resources and breeding
Although it is a very variable species, it is unlikely that substantial germplasm collections are being maintained and there are no breeding programmes.
Batiki blue grass is a useful forage plant in several areas of South-East Asia and the Pacific Islands. It is a competive grass and resists weed invasion. It is palatable, well grazed and can persist under heavy grazing. There are good prospects for its use, especiallly in plantation crops and in moist areas. Germplasm collections of this species are needed so that its variability can be assessed and utilized in agronomic studies for the release of new cultivars to farmers.
- Bor, N.L., 1960. The grasses of Burma, Ceylon, India and Pakistan (excluding Bambuseae). Pergamon Press, Oxford. pp. 180-182.
- Dunsmore, J.R. & Ong, C.B., 1969. Preliminary work on pasture species and beef production in Sarawak, Malaysia. Tropical Grasslands 3: 117-121.
- Gilliland, H.B., Holttum, R.E. & Bor, N. L., 1971. Grasses of Malaya. In: Burkill, H.M. (Editor): Flora of Malaya. Vol. 3. Government Printing Office, Singapore. p. 263.
- Häfliger, E. & Scholz, H., 1980. Grass weeds 1. Ciba-Geigy Ltd., Basel, Switzerland. p. 64.
- Ng, T.T., 1976. Performance of some tropical grass-legume mixtures in Sarawak. Malaysian Agricultural Journal 50: 400-410.
- Ranacou, E., 1986. Review of research and recorded observations on pastures in Fiji (1920-1985). III. Batiki blue grass (Ischaemum indicum). Fiji Agricultural Journal 48: 24-29.
- Skerman, P. J. & Riveros, F., 1990. Tropical grasses. FAO, Rome. 474-477.
- Veldkamp, J.F., 1991. Miscellaneous notes on Southeast Asian Gramineae. Blumea 36: 180-181.
B.B. Baki, I.B. Ipor & C. Manidool