Cymbopogon citratus (DC.) Stapf
Family
Gramineae
Synonyms
Andropogon citratus DC., A. ceriferus Hackel, A. nardus (L.) Rendle var. ceriferus Hackel.
Vernacular Names
| Malaysia | Sereh, serai, serai dapur |
| English | Lemongrass, West Indian lemongrass |
| Indonesia | Serai dapur (General), sereh (Sundanese), bubu (Halmahera) |
| Philippines | Tanglad, salai(Tagalog), balioko (Bisaya) |
| Cambodia | Slek krey sabou |
| Laos | ‘si khai, ‘sing khai |
| Burma (Myanmar) | Sabalin |
| Thailand | Cha khrai (Northern), khrai (Peninsular), soet-kroei (Eastern) |
| Vietnam | S[ar] chanh |
| French | Herbe-citron, verveine des Indes |
Geographical Distributions
The exact origin of C. citratus is not known but a Malesian origin is most likely. C. citratus is only known from cultivation and it has been cultivated for several centuries in South and South-East Asia. After the First World War large-scale cultivation was taken up in South and Central America and later in Madagascar and nearby islands and in Africa. C. citratus is now found cultivated and often naturalised throughout the tropics and warm sub-tropics e.g. in southern parts of the Russian Federation and northern Australia. It is very commonly cultivated throughout South-East Asia both as an industrial and as a garden crop, e.g. in Java it is planted in nearly every home garden.
Description
This is a perennial, tufted, aromatic grass with numerous erect culms arising from a short, oblique, ring-shaped and sparingly branched rhizome. The stem is smooth, solid at the bottom and is up to 2(-3) m tall with waxy powdery secretion below the nodes.
Leaves are leathery-textured sheaths. They are smooth and cylindrical, tightly embracing the stem, striate with basal ones persistent. The elongated flattened strap-shaped structure is less than 2 mm long, rounded or truncate, papery and hairless. The blade is linear, 50-100 cm x 0.5-2 cm with long-attenuate at both ends. Their hairless apex is acuminate, drooping and waxy bluish-green. The midrib is prominent below and white above, smooth on both surfaces but top part and margins are often rough.
The 4-9-noded inflorescence is large, loose and compounded, nodding stalk up to 60 cm longand repeatedly branched. Each division is issuing from a spoon-like sheath with or without a leaf until the final ramification is a flower stalk carrying a pair of racemes. The raceme is 1.5-2.5 cm long, its rachis is villous with 2-3 mm long hairs It bears 4-7 pairs of a secondary simple indeterminate inflorescence size between 5-6 mm x 0.7 mm and bearing 2 florets. Each pair is sessile while the other has a stalk. They are terminated by 1 sessile and furnished with stalk of individual flowers. . The 2-keeled, hairless and less veined lower chaff of the grass inflorescence is flat or shallowly concave on the back with similar size and shape to the secondary simple indeterminate inflorescence. The upper grass inflorescence is boat-shaped and I-keeled on the back. The lower floret is reduced to an empty lemma while the upper floret is hermaphrodite, less a bristle-like appendage, with hyaline and 2-lobed lemma. There are no bracts enclosing the flowers. They have 2 lodicules, wedge-shaped or truncate with 3 stamens and 2 styles with plumose stigmas. The secondary simple indeterminate flowers are furnished with 4.5 mm long stalk and they are either male or reduced to empty glumes. The lower grasses inflorescence is 7-9-veined while the upper is 3-veined.
Seed is a cylindrical to slightly spherical caryopsis with basal scar left on the seed.
Ecology / Cultivation
C. citratus grows best under sunny, warm and humid conditions. It performs best below 500 m altitude, but is grown up to 750 m in Madagascar and the Comoros. Average daytime temperatures of 23-30°C without extremely low night temperatures are optimum for growth and yield. Short periods with a daily maximum temperature over 30°C do not harm growth but severely reduce oil content. Hot dry winds may not only desiccate the crop but can also evaporate the oil. Frost is normally fatal. Water requirement is very high; the highest yields are obtained where the average annual rainfall is 2500-3000 mm evenly distributed over the year. Up to 5000 mm is tolerated on well drained soils. Long periods of dry sunny weather strongly reduce herbage yield and oil yield, although oil content is generally higher during the dry season. Good drainage is the most important soil requirement for C. citratus and in many countries plantations are on sandy soils, though loamy soils are used e.g. in China, Madagascar and Vietnam. Generally, soils of C. citratus plantations have a pH of 5.5-7.5, although good growth has been observed in Australia on a clay soil with pH 9.6. Good growth was also found on acid peat soils in Sarawak, Malaysia (pH 4.5). Saline soils are considered unsuitable, although fair growth and oil yield on saline soils have been obtained in greenhouse experiments.
Line Drawing / Photograph
Read More
1) Cultivation
References
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Plant Resources of South-East Asia No 19: Essential-oil plants.
