Volume 8 > Part 2 > Year 2007 > Page 418 > Euphorbiaceae > Mallotus

27. Mallotus peltatus (Geisel.) Müll.Arg.wfo-0000234686

Linnaea 34: 187. 1865; Airy Shaw, Kew Bull. 26: 307. 1972; Whitmore, Tree Fl. Malaya 2: 113. 1973; Welzen, Slik & Bollendorff in Welzen et al., Thai Forest Bull.(Bot.) 28: 103. 2000; Slik & Welzen, Blumea 46: 41, fig. 16, map 7. 2001.— Aleurites peltatus Geisel., Croton. Monogr.: 81. 1807. Fig. 32.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Shrub to tree, up to 10 m high, often (faintly) smelling of fenugreek. Indumentum of few short or long simple hairs, short stellate hairs, few glandular scales. Stipules triangular, 2–4 by 0.7–1.5 mm. Leaves alternate to opposite; petiole 0.4–7cm long; blades ovate to obovate, 6–23 by 2.3–10 cm, length/width ratio 1.8–3.8, drying brownish, base deeply emarginate to round (to cuneate), not peltate to peltate up to 14 mm, margin subentire to usually denticulate with glandular teeth, apex cuspidate to caudate, upper surface glabrous, basally with 2–6 small blackish extrafloral nectaries on nerves below insertion, ca 0.3–0.5 mm in diam., lower surface subglabrous, few glandular scales, usually pocket tufts in nerve axils; venation palmate. Inflorescences terminal to axillary, single or 2 together, unbranched. Staminate inflorescences up to 16 cm long; flowers in groups of up to 9 per node; bracts triangular, 0.9–1 by 0.9–1 mm. Staminate flowers 3–4.5 mm in diam., scented; pedicel 1.6–2 mm long, green; sepals 2–4, ovate to elliptic, 1.6–3 by 0.7–1.3 mm, yellowish-light green; stamens 25–35, filaments 1–3.2 mm long, light (yellowish) green to white; anthers 0.2–0.3 mm long, cream. Pistillate inflorescences up to 21.5 cm long; bracts ovate, 2–2.9 by 1.6–1.7 mm. Pistillate flowers 3–4 mm in diam., green (to red); pedicel 2(–4.5 in fruit) mm long; calyx urceolate, enclosing ovary and style closely, 4–6 mm high, apically with 2 small lobes, ca 1.2 by 0.7–1.3 mm, tearing apart and caducous, leaving ring-like scar in fruit, light yellow; ovary 3-locular, 1–2 by 1–2 mm, covered with spines up to 0.7 mm long; styles 2.8–4.5 mm long; stigmas 3–4.5 mm long, light yellowish. Fruits lobed capsules, 1–1.4 by 0.5–0.75 cm, green to wine red to brown with sparse, caducous, reddish spines and yellow glandular scales, subglabrous; column 3.3–4.5 mm long. Seeds subglobose, 4–5 mm in diam., brown, often marbled.

Thailand : NORTHERN: Chiang Mai, Phayao, Lampang, Phrae, Uttaradit, Sukhothai, Nakhon Sawan; EASTERN: Chaiyaphum, Nakhon Ratchasima; SOUTH-WESTERN: Uthai Thani, Kanchanaburi, Prachuap Khiri Khan; CENTRAL: Saraburi, Nakhon Nayok; SOUTH-EASTERN: Prachin Buri, Chon Buri, Rayong, Chanthaburi; PENINSULAR: Ranong, Surat Thani, Phangnga, Phuket, Krabi, Nakhon Si Thammarat, Phatthalung, Trang, Satun, Songkhla, Pattani, Yala, Narathiwat.

Distribution : Burma, Andaman Islands, Indochina, throughout Malesia to New Guinea.

Ecology : In a large variety of vegetations, varying from deciduous (mixed) forests to evergreen forests, bamboo forests, mixed oak forests, often along water or in rocky areas, also in very disturbed places, like thickets, edges of forests, fields; soil: shale, limestone or granite bedrock; 0–800 m alt.

Vernacular : Salat (สลัด)(Chanthaburi); khi tao (ขี้เต่า)(Ranong).

CommonName : Wild castor oil.

Notes: Two widespread species in Thailand, Mallotus oblongifolius and M. peltatus, have been united. The only difference between the two species is the absence or presence of a peltate leaf base. In all other characters, though often very variable (see number of synonyms), they are the same. However, specimens with peltate leaves often also have non-peltate leaves (referred to M. peltatus), and specimens with non-peltate leaves often have slightly peltate leaves (always referred to M. oblongifolius). The peltation seemingly shows a continuum in Thailand and the separation into two species is artificial. Unfortunately, both names, of which peltatus is the oldest, are ill-fitting, many specimens are not peltate and very often the leaves are clearly ovate or elliptic instead of oblong. The combined taxon is highly distinctive due to its long acuminate staminate sepals, leaves which are almost devoid of hairs and glandular scales, and the high, urceolate pistillate calyx.