Malesian Euphorbiaceae Descriptions

101. TRIADICA

 

Esser, H.-J. 1999. A partial revision of the Hippomaneae (Euphorbiaceae) in Malesia. Blumea 44: 149–215.

 

Phylogeny of the Hippomaneae

 

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Genus description

Key to the species

Species descriptions

 

Triadica Lour.

 

    Triadica Lour., Fl. Cochinch. ed. 1, 2 (1790) 598, 610; ed. 2, 2 (1793) 735, 748; A.Juss., Euphorb. Gen. (1824) 50; Rchb., Consp. regn. veg. (1828) 194; Hurus., J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6 (1954) 315; Kruijt, Biblioth. Bot. 146 (1996) 7; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 123; Esser, Blumea 44 (1999) 200; in Radcl.-Sm., Gen. Euphorbiacearum (2001) 379; Harvard Pap. Bot. 7 (2002) 17; in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 571; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 194. — Stillingia sect. Triadica (Lour.) Baill., Ιtude Euphorb. (1858) 511; Adansonia 1 (1861) 351. v Sapium sect. Triadica (Lour.) Mόll.Arg., Linnaea 32 (1863) 121; Hook.f., Fl. Brit. India 5 (1888) 469; Pax in Engl. & Prantl, Nat. Pflanzenfam. 3, 5 (1890) 98, fig. 63; T.Post & Kuntze, Lex. Gen. Phan. (1903) 498; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.v (1912) 237; in Engl. & Harms, Nat. Pflanzenfam. ed. 2, 19c (1931) 201; G.L.Webster, J. Arnold Arbor. 48 (1967) 392. — Excoecaria sect. Triadica (Lour.) Mόll.Arg. in DC., Prodr. 15, 2 (1866) 1210. — Lectotype (designated by G.L.Webster, 1994: 123): Triadica sinensis Lour. [= Triadica sebifera (L.) Small].

    [Stillingfleetia Bojer, Hortus Maurit. (1837) 284, nomen. — Based  on: Stillingfleetia sebifera (L.) Bojer [= Triadica sebifera (L.) Small].]

    Seborium Raf., Sylva Tellur. (1838) 63. — Type: Seborium chinense Raf. [= Triadica sebifera (L.) Small].

 

Trees. Monoecious. Flowering and fruiting twigs with leaves. Indumentum absent, although some organs are erose-ciliate. Stipules ovate to triangular, 0.5–2 mm long, undivided, glandless. Leaves alternate, but sometimes apically crowded; petiole 1–6 cm long, at least half as long as blade, usually glandless (but basilaminar glands sometimes on the petiole apex, see below); blade orbiculate to elliptic to slightly ovate, 2.5–7 cm wide, base cordate to acute to attenuate, margin entire, apex obtuse to mucronate to acuminate, above with a pair of large, nearly globose-spheroidal glands on the base (sometimes more on the petiole apex), lower surface papillate and pale to distinctly whitish-farinose, often with a row of few submarginal glands not touching the margin, secondary veins distinct, lowermost pair originating from the very leaf base and forming the basal leaf margin, with a different angle with the midrib, intersecondary veins present, smaller veins reticulate. Inflorescences terminal and in axils of uppermost leaves, yellowish, not compound, without sterile basal region, pistillate flowers at base of staminate part, staminate part 25–140 by 5–10 mm. Bracts of staminate cymules triangular, acuminate, basally with a pair of spheroidal-cylindrical glands touching the axis of the thyrse or slightly decurrent. Staminate cymules (3–)5–8-flowered; bracteoles present, nearly as long as the bracts, undivided, margin slightly ciliate. Staminate flowers with distinct (> 2 mm long) pedicel in bud and when flowering; calyx fused for the most part with a varying number of lobes (3–6); stamens 2 or 3, filaments longer than anthers. Pistillate flowers with pedicel 2–10 mm long; calyx with 3, sometimes apically to completely divided sepals, glandless or sometimes with spheroidal glands at margin; ovary 3-locular, smooth; style present, disarticulating at base, stigmata 3, undivided, glandless. Fruits with pedicel 2–15 mm long; 3-seeded, smooth, dry, opening regularly and nearly simultaneously septicidally and loculicidally; mericarps with moderately thick pericarp, septa largely remaining at central columella, mericarps therefore hardly with septal remnants, basally without separate triangle, with one apical vascular bundle; remaining columella conspicuously alate, persistent. Seeds attached to the central columella for a considerable time after ripening, covered with a pale to whitish sarcotesta, without caruncle.

    Distribution — Three species, all in Asia and mostly distributed in E. Asia (Indo-China, China); only one species in W Malesia up to Celebes and Palawan (Philippines).

    Note — Although the genus is well-defined by its fruits and some leaf characters, the relations of some species actually included in Sapium still have to be examined. Especially S. rotundifolium Hemsl. will probably prove to belong to Triadica.

 

Key to the species

 

1a.

Leaves ovate to elliptic, at least twice as long as wide.

1. Triadica cochinchinensis

1b.

Leaves broadly ovate, less than twice as long as wide.

2. Triadica sebifera

 

1. Triadica cochinchinensis Lour. 

 

    Triadica cochinchinensis Lour., Fl. Cochinch. ed. 1, 2 (1790) 610; ed. 2, 2 (1793) 749; Esser, Blumea 44 (1999) 201, Fig. 7; Map 7; Harvard Pap. Bot. 7 (2002) 18; in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 573, Fig. 91, Plate XXX: 2. —Excoecaria loureiroana Mόll.Arg. in DC., Prodr. 15, 2 (1866) 1217, nom. nov. — Sapium cochinchinense (Lour.) Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.v (1912) 252; S.Moore, J. Bot. 63 (1925) 288; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1926) 395, 401; Merr., Trans. Amer. Philos. Soc., n.s. 24 (1935) 241. — Shirakia cochinchinensis (Lour.) Hurus., J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6 (1954) 318; Kruijt, Biblioth. Bot. 146 (1996) 93. — Type: Loureiro s.n. (holo BM; iso BM), Cochinchina.

    Stillingia discolor Champ. ex Benth., Hook. J. Bot. Kew Gard. Misc. 6 (1854) 1. — Sapium discolor (Champ. ex Benth.) Mόll.Arg., Linnaea 32 (1863) 121; Hook.f., Fl. Brit. India 5 (1888) 469; Boerl., Handl. Fl. Ned. Ind. 3, 1 (1900) 295; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.v (1912) 239; Ridl., Fl. Malay Pen. 3 (1924) 316; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1926) 394, 395, 399, fig. 46.2–8; Merr., Philipp. J. Sc. 30 (1926) 404; Burkill, Dict. Econ. Prod. Malay Pen. 2 (1935) 1960; Corner, Ways. Trees Malaya 1 (1940) 276; Kτriba, Gard. Bull. 17 (1958) 19, 70; Wyatt-Smith, Malay. For. Rec. 17 (1965) 113, 344; Hallι, Biotropica 3 (1971) 57, 59, fig. 5; Whitmore, Tree Fl. Malaya 2 (1973) 129; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 192; Hsieh, Fl. Taiwan 3 (1977) 494; Airy Shaw, Kew Bull. 36 (1981) 341; Alph. Enum. Philipp. Euphorb. (1983) 44; Chakrab. & M.Gangop., J. Econ. Tax. Bot. 14 (1990) 183; ‘t Mannetje & Jones (eds.), Pl. Res. SE Asia (PROSEA handb.) 4, Forages (1992) 252; P.H.Hτ, Cβyco Viκtnam 2, 1 (1992) 355; I.M.Turner, Gard. Bull. 47 (1995) 231; Y.C.Tseng, Fl. Reipubl. Pop. Sin. 44(3) (1997) 18. — Excoecaria discolor (Champ. ex Benth.) Mόll.Arg. in DC., Prodr. 15, 2 (1866) 1210; Kruijt, Biblioth. Bot. 146 (1996) 88. — Lectotype (designated by Esser, 1999): Champion s.n. (holo K; iso GH, K), Hongkong.

    Stillingia ? lanceolaria Miq., Fl. Ind. Bat. Suppl. 1 (1861) 183, 461; Airy Shaw, Kew Bull. 36 (1981) 342. — Excoecaria ? lanceolaria (Miq.) Mόll.Arg. in DC., Prodr. 15, 2 (1866) 1221; Boerl., Handl. Fl. Ned. Ind. 3, 1 (1900) 296; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.v (1912) 170. — Type: Teijsmann HB 549 (holo U; iso CAL, n.v.), Sumatra, Padang, Poeloe Pisang.

 

Triacoch-habit.gif (222215 bytes)    Triacoch-male.gif (123711 bytes)    Triacoch-fruit.gif (108015 bytes)    Triacoch-photo.jpg (111430 bytes)

 

Shrub to tree, up to 25 m high, stem 40 cm in diam., bole up to 20 m high, without buttresses. Deciduous with crown bare for 1–2 weeks. Bark rather smooth, not fissured, light grey to brown; inner bark granular mottled, pale to yellowish to orange. Sapwood pale yellow to white, soft; sapwood and heartwood little differentiated. Stipules 0.3–2 by 0.6–0.7 mm. Leaves pinkish when young, withering blood red; petiole 1–3 cm long; blade slightly ovate to elliptic, (2.5–)3.5–7 by 1–3 cm, less than half as wide as long, base cuneate to attenuate to rarely obtuse, apex obtuse to acute to acuminate, above with a pair of basal glands 1–1.5 by 0.5–0.75 mm, lower surface whitish-papillate to whitish-glaucous and with 0–3 glands per side, 0.5–1 mm in diam. and (0–)0.5–1 mm distant from margin, secondary veins 9–17 pairs, angle with midrib 65–76°, arching but only indistinctly joining towards the margin, lowermost pair with angle with midrib 30–45°. Inflorescences: staminate part 25–50 by 7–10 mm. Bracts of staminate cymules 1–1.5 mm long, their glands 1–1.5 by 0.5–0.75 mm. Staminate flowers: pedicel 2–3 mm long, articulate near base; calyx c. 1 mm long; stamens with filaments 0.75–1 mm long when flowering, anthers 0.4–0.5 mm long. Pistillate flowers 0–13 per thyrse; pedicel 2–4 mm long; calyx 1–2 mm long, sepals rarely with basimarginal glands; style 1–3 mm long, stigmata 2–3 mm long. Fruits: pedicel 2.5–6 mm long; schizocarp circular in outline, 7–9 by 7–9 mm, base often clavate, slightly or not sulcate, apex rounded; pericarp 0.3–0.4 mm thick; remaining columella distinctly alate by 1.5–2.5 mm, marginally with conspicuously arching vein. Seeds 3.5-5 by 3.5–4.5 by 2.5–3 mm, sarcotesta pale but hardly white, brownish when dry.

    Distribution — NE India, Myanmar (Burma), Thailand, Indochina up to Taiwan and China (up to Hubei and Zheijang), and W Malesia: Malay Peninsula (incl. Singapore), Sumatra, N Borneo (Sabah, Sarawak), Philippines (Palawan), and Celebes.

 

Triadcoch-map.gif (36187 bytes)

 

    Habitat & Ecology — Found in primary forest, disturbed forest, young secondary forest of 5 years, and thickets, on hillsides and steep slopes, also in dry places. Soil: yellow and granitic sand. Fairly common. Altitude 10–1,100 m. Flowering: January, April, May, August, September, November; fruiting: the whole year through.

    Uses — ‘t Mannetje & Jones (1992) cite the species as a timber tree, additionally as minor forage plant. The wood is soft, light and not of great use (Burkill, 1935). The seed coat is poorer in palmitic acid than that of T. sebifera, and is therefore not used (Aziz, 1987).

    Vernacular names — Malay Peninsula: Mamah pelandok. Sumatra: Ludai. Borneo: Sengajang, tapang lalat (Ibang).

    Notes — 1. The combination Sapium cochinchinense (Lour.) Kuntze, Revis. Gen. Pl. 3(2) (1898) 293 refers to Excoecaria cochinchinensis Lour., not to T. cochinchinensis Lour. Most subsequent authors, like Pax & Hoffmann (1912) and Merrill (1935) used it for Triadica (under "Sapium").

2. Usually, all specimens from Malesia and southern Cochinchina may be distinguished from the plants of the northern part of its range (including the lectotype) by the lower surface of the leaves more distinctly whitish. The structure of the cuticular ornamentations is obviously different. The syntypes of Stillingia discolor represent both variants. However, a taxonomic separation cannot be corroborated. Croizat's (1940) statement that it "is a collective species with numerous local forms" probably is not justified. Chakrabarty & Gangopadhyay (1990) united the species with the Indian S. eugeniifolium Buch.-Ham., which had been already suggested by Hooker (1888); both taxa had been kept separate before because of differences of the leaves very similar to the differences between the two mentioned syntypes. Considering the variability of T. cochinchinensis over its whole range, also Sapium laui from Hainan, described by Croizat (1940) for slight differences of leaves and mesurements, may prove to be synonymous with T. cochinchinensis.

 

2. Triadica sebifera (L.) Small

 

    Triadica sebifera (L.) Small, Man. S.E. Fl. (1933) 789; Hurus., J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6 (1954) 315, fig. 45; Kruijt, Biblioth. Bot. 146 (1996) 89; Esser, Blumea 44 (1999) 204. — Croton sebiferus L., Sp. Pl. (1753) 1004. — Stillingia sebifera (L.) Michx., Fl. Bor.-Amer. 2 (1803) 213; Willd., Sp. Pl. ed. 4, 4, 1 (1805) 588; Hassk., Cat. Hort. Bot. Bogor. (1844) 234; Baill., Ιtude Euphorb. Atlas (1858) pl. 7, fig. 26–30; Miq., Fl. Ind. Bat. 1, 2 (1859) 413. — Sapium sebiferum (L.) Roxb. [Hort. Bengal. (1814) 69, nomen] Fl. Ind. ed. 1832, 3 (1832) 693; Wall., Numer. List. (1847) 7972; Mόll.Arg., Linnaea 32 (1863) 121; Hook.f., Fl. Brit. India 5 (1888) 470; G.Watts, Dict. Econ. Prod. India 6, 2 (1893) 472; Boerl., Handl. Fl. Ned. Ind. 3, 1 (1900) 295; J.J.Sm. in Koord. & Valeton, Bijdr. Boomsoort. Java 12 (1910) 613; Koord., Exkurs.-Fl. Java 2 (1912) 507; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.v (1912) 237; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1926) 394, 395, 398; Burkill, Dict. Econ. Prod. Malay Pen. 2 (1935) 1962; F.N.Howes, Kew Bull. 1949 (1950) 573; K.Heyne, Nutt. Pl. Indon. ed. 3, 1 (1950) 961; Backer & Bakh.f., Fl. Java 1 (1964) 500; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 136, 192; Hsieh, Fl. Taiwan 3 (1977) 496, pl. 700. — Seborium chinense Raf., Sylva Tellur. (1838) 63, nomen superfl. — Stillingfleetia sebifera (L.) Bojer, Hort. Maurit. (1857) 284. — Excoecaria sebifera (L.) Mόll.Arg. in DC., Prodr. 15, 2 (1866) 1210. — Carumbium sebiferum (L.) Kurz, Forest Fl. Burma 2 (1877) 411, 412. — Seborium sebiferum Hurus., Bot. Mag. Tokyo 61 (1948) 30. — Lectotype (designated by Radcliffe-Smith, Fl. Pakistan 172, 1986: 86): Osbeck s.n. in Herb. Linn. No. 1140.9 (LINN, n.v.), China, Canton.

    Triadica sinensis Lour., Fl. Cochinch. ed. 1., 2 (1790) 610; ed. 2, 2 (1793) 749; Baill., Ιtude Euphorb. (1858) 512; Merr., Trans. Amer. Philos. Soc., n.s. 24 (1935) 241. — Type: Loureiro s.n. (holo BM, n.v.), Cochinchina, "circa Cantonem Sinarum".

 

Shrub to tree, up to 8 m high. Deciduous. Leaves: petiole 2.5–4 cm long; blade broadly ovate to orbicular, 3.5–6.5 by 2.5–7.5 cm, more than half as wide as long, base rounded, apex acuminate, above with a pair of glands c. 0.75 mm in diam., lower surface whitish-papillate and with no to few submarginal glands, secondary veins 8–10 pairs, arching and joined towards the margin, smaller veins closely and distinctly reticulate. Inflorescences 70–140 mm long. Bracts: glands c. 1 by 0.75 mm. Pistillate flowers 2–6 per thyrse. Fruits: pedicel 6–15 m long; schizocarp c. 12 mm long, sulcate. Seeds 6.5–8 by 6.5–7 mm, with a white, persistent sarcotesta.

    Distribution — Native to China (known from nearly all provinces: Lee, 1956) and Taiwan. For its different uses often cultivated in warmer regions and sometimes naturalizing, nowadays in the USA, N India, and Japan, in former times also grown in Mauritius, Indochina, and Malesia (Singapore, Bogor, Timor; compare note 2).

    Habitat & Ecology — Growing well e.g in moist soil or near waters, and thriving under a wide range of soil conditions. It is frost hardy. It flowers after three years with very fragrant flowers; the fruits take three to four months for ripening (Aziz, 1987).

    Uses — There is a wealth of literature available concerned with cultivation and uses in regions outside Malesia, especially China, Japan, India, and the USA (e.g., Howes, 1950). The species is planted as ornamental and has positive effects when planted as shade tree in plantations of other crops, especially as the species grows very well and often tends to naturalize easily. It is also a minor timber tree, and the leaves provide a black dye. The waxy seed coat yields the ”vegetable tallow” used for candle-making and soaps in China, whereas the endosperm of the seeds provides a drying oil (Stillingia oil) with properties similar to tung oil, in its drying capacities comparable to linseed oil, but also used as an illuminant (Burkill, 1935) and for waterpoofing umbrellas (Lee, 1956).

    Vernacular names — Java: Kasoembi, kirendang (Smith, 1910).

    Notes — 1. T. sebifera has often been confused with species of Homalanthus, especially H. populneus (Geiseler) Pax. Airy Shaw (1975) cites some examples of erroneous records of T. sebifera for Malesia. Homalanthus species may be distinguished from Triadica by the remarkable large stipules, leaves with percurrent (not reticulate) tertiary venation, different adaxial leaf glands, 3-flowered staminate cymules with compressed flowers and numerous stamens, and by very different, smaller fruits with mostly two carpels, a thin and fleshy pericarp, and seeds with a reddish arilloid.

2. Although quite often cited in the literature regarding Malesia, only four collections from this region could be studied [Horsfield s.n., Java (BM); Teijsmann s.n., Java (P, K); de Vriese s.n., L 904117-515, Java, Bogor Bot. Gard. (L); R. Brown s.n., Timor (BM)]. The other localities cited were taken from the literature. Obviously, the cultivation in Malesia has been abandoned, and no records from the 20th century are available.