Coix lacryma-jobi L.
Coix lacryma L., Coix agrestis Lour., Coix arundinacea Lamk.
|Malaysia||Jelai batu, jelai pulut, menjelai.|
|English||Job's tears, adlay.|
|Indonesia||Jali, jali betul, jali watu.|
|Philippines||Adlai (Bisaya), kaudlasan (Tagalog), katigbi (Tagalog).|
|Thailand||Duai (General), maduai (Northern).|
|Vietnam||[ys] d[ix], bo bo, c[uw][owf]m g[aj]o.|
|French||Larmes de Job, larmilles, herbe à chapelets.|
Note: The Arabs, who introduced the plant to the west, named it 'Damu Ayub' (Job's tears), because its false fruit resembles a tear-drop. This name has been adopted in several other languages.
The origin of Coix lacryma-jobi is unknown, but it is indigenous to southern and eastern Asia. The form with a soft-shelled false fruit (var. ma-yuen (Romanet) Stapf) has been cultivated since ancient times which is 3000-4000 years ago in India, 2000 years ago in China and was very important before maize and rice became widespread as staple foods. At present, it is cultivated as a minor cereal crop throughout the tropics and subtropics, especially in India, China, the Philippines, Thailand, Malaysia and the Mediterranean. Forms with hard-shelled false fruit are also occasionally cultivated. The plants escaped from cultivation occur as weeds.
C. lacryma-jobi is an erect, perennial, strongly tillering, monoecious grass and often cultivated as an annual that can grow up to 3 m tall. The culm is filled with pith, hairless, sometimes pruinose and it branched in the upper part.
The leaves are large and sheathed. The sheath is short and smooth or with long hairs at the apex. The ligule is short and membranous. The auricles are absent. The blade is linear to ovate-lance-shaped, measuring 8-100 cm x 1.5-5 cm, rounded to almost cordate at the base, acute at the apex, prominent at the midrib, with rough margins and smooth or scabrid above.
The inflorescence is in the axil of the upper leaves, solitary or 2-7-fascicled and on a peduncle measure 3-6 cm long. At the end of the peduncle is a hollow, bony, with a globular to ovoid-elliptical cupule (a modified leaf-sheath), measures 5-15 mm long, shiny, white or blueish and comprises of 2 racemes. The female raceme is enclosed by the cupule and consists of a sessile spikelet that accompanied by 2 barren pedicels. The spikelet is with 1 pistillate floret of which the 2 stigmas exsert from the mouth of the cupule. The male raceme is 3-5 cm long, exserted from the mouth of the cupule and with about 10 imbricate spikelets that borne in pairs or threes where one is pedicelled while the other(s) are sessile. The spikelet is lance-shaped to ellipsoid, measures 7-8 mm long, falling at maturity, contains 1-2 staminate florets where each is with a lemma, a smaller palea and 3 stamens.
The false fruit (the cupule) is variable in size, shape, colour and hardness, usually 8-12 mm long, grey yellow-brown or purplish, soft or hard and contains caryopsis. The caryopsis is dark red in hard-shelled forms which is pale brown in soft-shelled edible forms.
C. lacryma-jobi is a quantitative short-day plant and requires high temperatures, abundant rainfall, reasonably fertile soils, and prefers short, sunny days. In the tropics, it occurs up to 2000 m altitude. It often grows wild in swampy locations.