Malesian Euphorbiaceae Descriptions

90. RICINUS

 

P.C. van Welzen

 

Welzen, P.C.  van. 1998. Revisions and phylogenies of Malesian Euphorbiaceae: Subtribe Lasiococcinae (Homonoia, Lasiococca, Spathiostemon) and Clonostylis, Ricinus, and Wetria. Blumea 43: 131164.

 

Because Ricinus has been introduced in Malesia only a qualitative description of the species is provided.

 

Ricinus communis L.

 

    Ricinus communis L., Sp. Pl. (1753) 1007; Müll.Arg. in DC., Prodr. 15, 2 (1866) 1017; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xi (1919) 119, fig. 29; W.H.Br., Bull. Dept. Agric. Nat. Res. Bureau Forestry 22 (1921) 143; Burkill, Dict. Econ. Prod. Malay Penins. 2 (1935) 1907; Heyne, Nutt. Pl. Indonesië, 3rd ed., 1 (1950) 928; G.L.Webster, J. Arnold Arbor. 48 (1967) 379, fig. 4; Arañez, Nat. Apl. Sc. Bull. 32 (1980) 53; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 158; Welzen, Blumea 43 (1998) 152; Radcl.-Sm., Gen. Euphorbiacearum (2001) 201; Welzen in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 517; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 116. Possible type specimens: Herb. Linnaeus no. 1142.1, -.2 (LINN), 392-11, -13 (S).

 

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Monoecious (herb to) shrub (to tree), up to 6 m high, d.b.h. up to 5 cm; stems green, brown, reddish or glaucous (when young), hollow or with some soft pith tissue. Indumentum absent. Bark reddish brown; inner bark pale grey; sapwood whitish. Extrafloral nectaries sessile or peduncled convex discs, at various places variously present: base and basal part of petiole, inside margins of stipule, base of leaf blade, base of bracts. Stipules united, opposite leaf, encircling stem, triangular, symmetric, parallel-nerved, caducous, leaving raised scar. Leaves alternate, simple; petiole long, often reddish; blade palmatifid with (6) 7(–11) broadly ovate to linear ovate lobes, symmetric, papery, green, red, or brown, base (narrowly) peltate, margin serrate with smaller and larger teeth, each with a terminal adaxial gland, apices of lobes acute, lower surface many glandular cells in epidermis, well visible when young, somewhat pitted when older; venation open, nerves ending in major teeth, part of veins on lower surface tinged light red to violet. Inflorescences terminal racemes or panicles with a few short branches, in fruit pseudo-axillary due to elongation of axillary buds, seldom very short truely axillary inflorescences with staminate flowers only, glaucous, with basally groups of staminate flowers, and apically 1 to a few pistillate flowers per node or a combination of pistillate and (non-opened) staminate flowers. Bracts triangular, dark brown to purplish. Flowers symmetric, pedicelled with abscission zone in upper third, fragrant; sepals 5, valvate, ovate, dehiscing often into 3 parts; petals and disc absent. Staminate flowers: sepals yellowish green, pale yellow; stamens many (> 100), united in many dichotomously splitting androphores, cream, white, or light yellow, anthers opening lengthwise, latrorse?, connective apically often with continuation of filament; pistillode absent. Pistillate flowers: sepals bract-like, early caducous, leaving a raised scar, green to red; ovary 3-locular, usually echinate outside with long papillae ending in a translucent stinging hair on top, ovules 1 per locule; style short; stigmas 3, light to deep red, connate to halfway, connate part above with long papillae, smooth below, split parts with short somewhat irregular papillae all over. Fruits capsular, somewhat lobed, higher than broad, falling septicidally apart in 3 bivalved parts, latter loculicidal except for apex, red to brown, smooth to sparsely to densely echinate; exocarp somewhat fleshy, sometimes dehiscing from mesocarp; mesocarp and endocarp woody; column tapering towards base, apex broadened, obtriangular in longitudinal section, septum remnant narrow, frayed, 1 vascular bundle per septum. Seed ellipsoid, dorsoventrally flattened, usually marbled with various shades of brown and white, shiny, apically with a 2-lobed caruncle. Embryo flattened, surrounded by a thin layer of endosperm. Seedling: cotyledons opposite, ovate, base emarginate with 2 glands adaxially at connection with petiole, margin entire, basally 3-nerved, nerves few, looped and joined near margin. First leaves like normal leaves but opposite, stipules 2, interpetiolar; all other leaves alternate with a single leaf-opposite stipule.

    Distribution Presumably originally from N. Africa, presently cultivated and occurring subspontaneously worldwide in tropical and subtropical areas; found throughout Malesia.

    Habitat & Ecology 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. Alt.: sea level up to 2400 m. Flowering and fruiting whole year through.

    Uses 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 fibers. 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 fordii). Other uses are in linoleum, leather, printing ink, lithographic varnishes, a special kind of soap, lubricants, 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 triricinolein (main component of castor oil) into glycerin and rininoleic acid; the latter irritates the intestines (Arañez 1980). The residual oil cake is poisonous and only buffaloes seem able to eat it, however, the cake is an excellent fertilizer (Burkill 1935).

Other uses, also mainly medicinal: Leaves and stem are used by the Dusun Kinabatangan (Borneo, Sabah) as remedy against stings and bites of insects and animals. Sap from heated petioles and young branches is used as ear drops (Indonesia). In the Philippines pound leaves applied as a poultice to the breast are recommended to stimulate milk secretion, boiled pound leaves may be used to wash ulcers and pounded roasted seeds mixed with oil can be applied over affected skin areas and is good for hemorrhoids; variations exist in other countries, but especially the leaves seem to act against all kinds of skin diseases. The seeds are eaten cooked in Irian Jaya (New 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). After Heyne (1950), Webster (1967), and Arañez (1980). Ornamental in Western countries.

    Vernacular names Dutch: Wonderboom. English: Castor bean. French: Ricin common. Thailand: La hoong (Southwestern, Kanchanaburi); mahung. Malay Peninsula: Jarak, jarak besar (Burkill 1935). Sumatra: Doelang bajora, kaliki. Java: Djarak kaliki (Sundanese); (d)jarak, djarak kepjar, djarak leutik, djarak poetih. Borneo: Kalimantan: Djarak tjina; Sabah: Dowar (Dusun); katimah (Dupe). Philippines: getlaoua, katana, lansina, taca-taca, talam-punai, tangan-tangan(-hawa), taua-taua(-sina) (Brown 1921; Arañez 1980). Lesser Sunda Islands: Flores: Padu goa, tai bara toko lakai (So’a, Ngadha). New Guinea: Irian Jaya: Labu (Dani); sebluk; Papua New Guinea: Fayita (Okapa); itumpa (Tairora); ovomasuro (Biagi); palawa-palawa-i(l) (Gododala). See also Heyne (1950, p. 928) for many more Indonesian names

    Notes 1. This species is morphologically very variable, presumably due to centuries of cultivation and escapes from cultivation (seeds are known from Egyptian pharaoh graves dating 4000 B.C.; Burkill 1935). 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 have been described for Malesia. Those which were described are often untraceable or refer to pre-Linnean names by Rumphius; only the material of one Blume type (Ricinus spectabilis) could be found in Leiden.

    2. Many cultivars are known, and new ones are still being bred. Growing of spineless fruits is one of the successful aims of today’s improvement schemes. Several races have oil of inferior quality and/or low quantity, while others produce high quality oil in sufficient quantity. Differences between races can be large and they have been used to describe several species. For one of the islands in the Pacific it was indicated that two forms were present, green plants and red ones, only the latter were used medicinally by Chinese. It was suggested that both forms represent different species. It cannot be repeated too often that recognizing species in man made cultivation systems is a very hazardous job and usually futile.