Ischaemum rugosum Salisb.

 

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Gramineae

Synonyms

  • Ischaemum colladoa Sprengel (1825)
  • Ischaemum segetum Trinius (1832)
Author: L.’t Mannetje

Common names

Wrinkle duck-beak, saramattagrass, wrinkle grass (En). Indonesia: suket blembem (Javanese), jukut randan (Sundanese). Malaysia: rumput mele (Sarawak), rumput ekor chawi, rumput colok cinia (Peninsular Malaysia). Philippines: tinitrigo (Tagalog), daua (Subanum), gulong lapas (Pangasinan). Burma: ka-gyi-the-myet. Cambodia: smao srauv. Thailand: ya daeng (central), ka-du-ai-nu, ya-noksichomphu.

Origin and geographic distribution

I. rugosum is indigenous to tropical Asia and is widely distributed throughout the tropics.

Description

A vigourous perennial or annual (in strongly desiccating soil) tufted grass, sometimes with stilt roots, rooting at the nodes, with erect, slanting or ascending, often much branched culms, up to 1.5 m tall. Leaf-sheath long-auricled, ciliate along outer margin, densely soft hairy on node; ligule a brownish truncate membrane, 1-7 mm long; leaf-blade linear, 10-40 cm x 1-4 cm, apex acute, rarely hairy with long slender hairs. Inflorescence terminal, well exerted, composed of 2 racemes that are firmly appressed together and interlocked when young, separating when mature, each 3-12 cm long; spikelets binate, dissimilar, one sessile at the abaxial side of the rachis, one stalked at the adaxial side, provided with a short blunt hairy callus; sessile spikelet 5-6 mm long, 2-flowered, lower floret male or neuter, upper one bisexual; lower glume strongly transversely 5-7-ribbed, and winged above; upper lemma deeply 2-cleft and with 1-2 cm long awn which is twisted basally; pedicelled spikelet more or less reduced, pedicel up
to 2 mm long, hairy, confluent with the callus. Caryopsis ovoid, 2 mm long, brown. It is a very variable species. Two varieties have been distinguished: var. rugosum, with developed pedicelled spikelets, and var. segetum Hackel, with much reduced pedicelled spikelets; they are not separated geographically (Baki and Manidool 1992).

Use

I. rugosum is used as forage. It is a serious weed in many crops, particularly in rice fields (Pancho1991). It also provides suitable material for compost and mulch. In times of scarcity the grain is eaten by people.

Properties

The forage quality of I. rugosum declines quickly with age of the material. Nitrogen concentration ranges from 0.5-1.2%.

 Toxicity

None has been reported.

Ecology

I. rugosum is an opportunistic and effective colonizer of open, disturbed or newly cleared areas. Although a sun-loving plant it can persist in sites receiving only 30-35% of full sunlight. It occurs at altitudes of up to 2400 m in the Philippines. I. rugosum is particularly well adapted to wet sites, and is often found in rice fields or low lying areas that are periodically flooded (Baki and Manidool 1992).

Soil requirements

It tolerates acid soils of pH(H2O) 4.0. Although it will persist on soils of poor fertility, it will respond to fertilizer application.

Propagation and planting

I. rugosum can be established by seeds or rooted culms. Newly harvested seeds appear to have innate or induced dormancy, and scarification is desirable to reduce hard-seededness. When sowing seed, good seedbed preparation assists in obtaining good establishment and seedling growth. Planting rooted culms at a 25 cm x 25 cm spacing will result in faster sward development than using seed (Baki and Manidool 1992)

Growth and development

Seeds germinate early in the wet season and grow vigorously. Swards may form a dense mass of sturdy culms 25-30 weeks after germination.

Diseases and pests

I. rugosum has no major diseases or pests. Infestations by Puccinia spp. are commonly observed; they may reduce the quantity and quality of feed available, but control by chemicals is not warranted. It is an alternative host of the viruses causing rice and maize leaf blight galls and of Piricularia sp.

Performance

It can be grazed, but will not persist when continuously grazed by large ruminants at high stocking rates. When it is growing in water, the tops above water level can be cut and fed to animals. It is usually fed when fresh, but can be ensiled or dried and conserved for dry season feeding.

Links

Link for the genus

References

Baki B.B. and Manidool C. (1992); Pancho, J.V. (1991)