Flora of Thailand



75. Ricinus


P.C. van Welzen


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Genus description

Species description




L., Sp. Pl.: 1007. 1753; Müll.Arg. in DC., Prod. 15, 2: 1017. 1866; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xi: 119. 1919; G.L.Webster, J. Arnold Arbor. 48: 379. 1967; Airy Shaw, Kew Bull. 26: 328. 1972; Arañez, Nat. Apl. Sc. Bull. 32: 53. 1980; G.L.Webster, Ann. Missouri Bot. Gard. 81: 158. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 201. 2001; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 517. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 116. 2014.Cataputia Ludw., Gen.: 81. 1760.


Shrubs (to trees), monoecious. Indumentum absent. Extrafloral nectaries sessile or peduncled convex discs, present at various places. Stipules united, opposite to leaf, encircling stem, caducous. Leaves alternate, simple, palmatifid with (6)7-9(-11) lobes, symmetric, papery, base (narrowly) peltate, margin serrate with smaller and larger teeth, each with a terminal adaxial gland; venation open, nerves ending in major teeth. Inflorescences usually terminal racemes or panicles with a few short branches, usually with basally groups of staminate flowers, and apically 1 to a few pistillate flowers per node. Flowers actinomorphic, pedicelled; sepals 5, valvate; petals and disc absent. Staminate flowers: anthers many (> 100), united in many dichotomously splitting androphores, connective apically often with an appendix; pistillode absent. Pistillate flowers: sepals bract-like, early caducous; ovary 3-locular; ovules 1 per locule. Fruits rhegmas, somewhat lobed, smooth to sparsely to densely echinate. Seeds ellipsoid, apically with a 2-lobed caruncle.

    Monotypic genus, see under the species for the distribution. Classification: Subfam. Acalyphoideae, tribe Acalypheae, subtribe Ricinae.


Ricinus communis L., Sp. Pl.: 1007. 1753; Müll.Arg. in DC., Prod. 15, 2: 1017. 1866; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xi: 119, fig. 29. 1919; W.H.Br., Bull. Dept. Agric. Nat. Res. Bureau Forestry 22: 143. 1921; G.L.Webster, J. Arnold Arbor. 48: 379, fig. 4. 1967; Airy Shaw, Kew Bull. 26: 328. 1972; G.L.Webster, Ann. Missouri Bot. Gard. 81: 158. 1994; Welzen, Blumea 43: 152. 1998; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 517, Fig. 69, 70, Plate XXVII: 2. 2007.


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Shrubs (to trees), up to 6 m high. Extrafloral nectaries variously present on base and basal part of petiole, inside margins of stipule, base of leaf blade, base of bracts. Stipules triangular, symmetric, parallel-nerved. Leaves green, red, or brown, apices of lobes acute, lower surface with many glandular cells in epidermis, easily visible when young, somewhat pitted when older. Flowers fragrant; sepals 5, dehiscing often into 3 parts. Staminate flowers: sepals yellowish green, pale yellow; stamens cream, white, or light yellow. Pistillate flowers: sepals green to red; ovary usually echinate outside with long papillae ending in a translucent stinging hair on top. Fruits red to brown; exocarp somewhat fleshy, sometimes dehiscing from mesocarp; mesocarp and endocarp woody. Seed usually marbled with various shades of brown and white, shiny.

    T h a i l a n d.NORTHERN: Phitsanulok; NORTH-EASTERN: Loei (Wangsa Phung); SOUTH-WESTERN: Kanchanaburi (Srisawat); CENTRAL: Saraburi (Tharn Pro Photisat). Cultivated or escaped, probably all over Thailand.

    D i s t r i b u t i o n.Presumably originally from N. Africa, presently cultivated and occurring sub-spontaneously world-wide in tropical and subtropical areas.

E c o l o g y. When semi-wild mainly found in waste places in all kinds of habitats on usually a rather rich soil, from sea shore to midmontane areas, scattered to locally common; however, also reported from the primary forest, but probably planted by villagers. Altitude: sea level up to 2400 m.

    V e r n a c u l a r.Khi-ti (คิติ) (Karen-Mae Hong Son); khi-to (คีเต๊าะ) (Karen-Kamphaeng Phet); pi-mua (ปีมั้ว) (Chinese); lahung (ละหุ่ง), malahung (มะละหุ่ง) (General); mahong (มะโห่ง), mahong hin (มะโห่งหิน) (Northern); lahung daeng (ละหุ่งแดง) (Central); castor bean, castor oil, palma-christi.

    U s e s.The main value is in the oil of the seeds (castor oil, wonder oil), but the plants also have a high horticultural value. The plant is cultivated in plantations and improvement schemes are carried out to increase its oil content. The oil from the seeds is used in the industry for a large variety of products and in medicine. It is a versatile fixed oil, which means that it can be altered chemically. It can be changed into sebacic acid, which is used to manufacture plastics and synthetic, durable fibres. The oil can also be changed into a drying oil for varnishes, enamels, and paints (softer, more elastic, and better resistant against yellowing than linseed or tung oil = Vernicia). Other uses are in linoleum, leather, printing ink, lithographic varnishes, a special kind of soap, lubricants, and sticky fly paper. When sulfonated it is used as a red dye (Turkey red oil). Medicinally it is mainly a purgative due to the fact that lipases change the triricinolein (main component of castor oil) into glycerin and rininoleic acid; the latter irritates the intestines. The residual oil cake is poisonous and only buffaloes seem able to eat it, however, the cake is an excellent fertiliser. Other uses are also mainly medicinal. The leaves and stem are used by the Dusun Kinabatangan (Borneo, Sabah) as a remedy against stings and bites of insects and animals. Sap from the heated petioles and young branches is used as ear drops (Indonesia). In the Philippines pounded leaves are applied as a poultice to the breast to stimulate milk secretion, boiled pounded leaves may be used to wash ulcers and pounded roasted seeds mixed with oil can be applied over affected skin areas and is also good for haemorrhoids; variations exist in other countries, but especially the leaves seem to act against all kinds of skin diseases. The seeds are eaten cooked in INew Guinea (n.b. uncooked seeds are toxic due to the phytotoxin ricin) or burned and used to paint hair or head black (Papua New Guinea) (Mainly after Araéez, 1980).

    N o t e.This species is morphologically very variable, presumably due to centuries of cultivation and escapes from cultivation (seeds are known from Egyptian pharaoh graves dating from 4000 B.C.). Therefore, only a qualitative description has been given of the species. Many species and infraspecific taxa have been described (see Müll.Arg., 1866; Pax & K.Hoffm., 1919), but all species names are synonyms of Ricinus communis (or synonyms of taxa accidentally confused with Ricinus). The infraspecific taxa and also species names probably refer to certain cultivars. No synonyms will be treated here, partly because there are too many and partly because few or none have been described for Thailand.