Flora of Thailand Euphorbiaceae

 

3. Agrostistachys

 

P.C. van Welzen & S. Sevilla

 

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Genus description

Identification key

Species descriptions

Agrostistachys

Dalzell, Hooker's J. Bot. Kew Gard. Misc. 2: 41. 1850; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 98. 1912; Airy Shaw, Kew Bull. 14: 472. 1960; Kew Bull. 26: 210. 1972; Whitmore, Tree Fl. Malaya 2: 52. 1973; G.L.Webster, Ann. Missouri Bot. Gard. 81: 69. 1994; Sevilla & Welzen, Blumea 46: 77. 2001; Radcl.-Sm., Gen. Euphorbiacearum: 132. 2001; Welzen & Sevilla in Chayam. & Welzen, Fl. Thailand 8, 1: 41. 2005; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 110. 2014. — Sarcoclinium Wight, Ic. Pl. Ind. Orient. 5: 24. 1852.—  Heterocalyx Gagnep., Notul. Syst. 14: 33. 1950.

Shrubs or trees, dioecious or monoecious. Indumentum consisting of simple hairs. Stipules early to late caducous, triangular to narrowly triangular. Leaves alternate, simple, symmetric, papery to coriaceous, base usually attenuate, margin entire to dentate with teeth ending in a gland, apex rounded to cuspidate, both sides smooth, glabrous; nerves pinnate, looped and joined near the margin, veins scalariform. Inflorescences cauliflorous to axillary spike-like thyrses, unbranched, usually several superposed. Flowers actinomorphic, sepals valvate; disc lobed (usually 5 lobes) to annular. Staminate flowers pedicellate, usually several per bract; sepals 2-5; petals (0-)5(-9); stamens 8-16, in a single or in two whorls, inner sometimes united, anthers 2-locular, basally deeply cleft or connective spade-like with anthers in basal lobes; pistillode absent (or present). Pistillate flowers pedicellate, single per bract; sepals (2-)5, petals 5, ovary (2- or) 3-locular, ovules 1 per locule, stigmas often sessile, split in upper part. Fruit a lobed rhegma, smooth. Seeds obovoid, apically carunculate.

    Eight species, from South India and Sri Lanka to S.E. Asia and throughout Malesia (Sumatra, Borneo, Philippines, New Guinea); 3 species in Thailand, one of which is a new record. Classification: Subfam. Acalyphoideae, tribe Agrostistachydeae.

Key to the species

1. Agrostistachys borneensis Becc., Nelle foreste: 331. 1902; Sevilla & Welzen, Blumea 46: 78, Fig. 2, 3e, f, h; Map 1. 2001; Welzen & Sevilla in Chayam. & Welzen, Fl. Thailand 8, 1: 41, fig. 8. 2005.— Sarcoclinium longifolia Wight, Ic. Pl. Ind. Orient. 5: 24, pl. 1887. 1852.— Agrostistachys longifolia (Wight) Trim., Syst. Cat. Ceylon Pl.: 81. 1885, nom. illeg.; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 100, fig. 49e. 1912; Whitmore, Tree Fl. Malaya 2: 53. 1973.—  Agrostistachys longifolia (Wight) Trimen var. latifolia Hook.f., Fl. Br. India 5: 407. 1887.—  Agrostistachys latifolia (Hook.f.) Pax & K.Hoffm. in Engl., Pflanzenr. VI.147.vi: 100. 1912.—  Agrostistachys leptostachya Pax & K.Hoffm. in Engl., Pflanzenr. VI.147.vi: 102. 1912.—  Agrostistachys coriacea Trim. in Trim. & Hook.f., Fl. Ceyl. 4, Suppl.: 265. 1931, nom. superfl.—  Agrostistachys longifolia (Wight) Benth. ex Hook.f. var. leptostachya (Pax & K.Hoffm.) Whitmore, Gard. Bull. Singapore 26: 52. 1972.

Shrubs up to 6 m high. Stipules ovate to triangular, 0.5-4 by 1-8 mm, late caducous, scars up to 1.5 cm below the leaves. Leaves: petiole 0(-2) cm long; blade narrowly to linear elliptic or obovate, 6-70 by 2-16 cm, length/width ratio 2-5.5, coriaceous, margin entire, nerves 10-40 per side, drying brownish. Inflorescences single to up to 4 superposed, up to 35 cm long, subsericeous to sericeous. Bracts ovate to obovate, 1-4 by 1-4 mm. Flowers single to 5 per bract. Staminate flowers 2-3 by 1.5-3 mm; pedicel 1-3 mm long; sepals 2-5, 1.5-2.5 by 1-2 mm, light orangish; petals 5, 1-2.5 by 1-2.5, light orangish; disc lobes 4-6; stamens 8-12 in two whorls, pale yellow, outer free, inner united with pistillode, free part of filaments 2-3 mm long; pistillode present. Pistillate flowers 2-4 by 2-3.5 mm; pedicel 2-5 mm long; sepals 5, 2-3 by 1-2 mm; petals 5, 1-2 by 1.5-2 mm; disc lobes 5; ovary 1-3 by 1.5-4 mm, stigmas sessile, 1-2.5 mm long. Fruits 6-9 by 5-7 mm. Seeds 4-6 by 3-5 mm.

    T h a i l a n d.— PENINSULAR: Satun (Nam Ra), Yala (A-machang).

    D i s t r i b u t i o n.— Sri Lanka, Thailand, Malay Peninsula, Sumatra, Borneo (type), Philippines, Papua New Guinea.

    E c o l o g y.— Primary and secondary forest, wet evergreen forest, dipterocarp forest, kerangas forest, montane (mossy) forest, swamp forest; in logged over forest, along forest paths and rivers, in open places; common in undergrowth and in open areas; soil: red, brown or yellow sandy clay, limestone, acidic sand. Altitude: 50-2000 m.

    V e r n a c u l a r.— Mai lao  (ไม้เหลา) (Peninsular).

    U s e s.— Burnt wood produces a black latex which is cosmetically used to dye the teeth black; the dyeing has to be repeated every three days.

2. Agrostistachys gaudichaudii Baill. ex Müll.Arg., Linnaea 34: 144. 1865; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 103. 1912; Airy Shaw, Kew Bull. 26: 210. 1972; Whitmore, Tree Fl. Malaya 2: 52. 1973; Sevilla & Welzen, Blumea 46: 81, Map 2. 2001; Welzen & Sevilla in Chayam. & Welzen, Fl. Thailand 8, 1: 42, plate II: 2. 2005.— Sarcoclinium gaudichaudii Baill., Étude Euphorb.: 310, 1858, nom. nud.— Agrostistachys maingayi Hook.f., Fl. Br. India 5: 406. 1887.— Agrostistachys filipendula Hook.f., Fl. Br. India 5: 407. 1887.

Shrubs or trees up to 15 m high. Stipules narrowly triangular, 2-20 by 2-7 mm, caducous, scars up to 4.5 cm below the leaves. Leaves: petiole 0.5-0.7 cm long; blade elliptic to obovate, 14-55 by 4.5-12 cm, length/width ratio 1.7-5.2, papery to subcoriaceous, margin entire to crenulate, nerves 11-24 per side, drying brownish (to yellowish). Inflorescences single to up to 15 superposed, up to 18 cm long, glabrous to subsericeous. Bracts broadly ovate, 2.5-5 by 2.5-6 mm. Flowers single to 3(-10) per bract, scented. Staminate flowers 2-3 by 2.5-3.5 mm, white to yellow to greenish; pedicel 2-3 mm long; sepals 3, c. 2 by 1.3-2 mm; petals 5, 1.3-1.5 by 1.2-1.5 mm; disc lobes 5, orange to red; stamens 10, in 1 whorl, free, filaments 1.5-3 mm long, yellow; anthers blue; pistillode absent. Pistillate flowers 2-3 by 2.5-3.5 mm; pedicel 0.2-1 cm long; sepals 5, 2-3 by c. 1 mm; petals 5, 1.5-3 by 1.5-3 mm, red-brown; disc annular; ovary 1-2.5 by 1.5-3 mm, stigmas sessile, 1.5-2 mm long. Fruits 5-12 by 8-15 mm, green to grey. Seeds 7-9 by 5-8 mm.

    T h a i l a n d.— PENINSULAR: Surat Thani (Tha Phet), Krabi (Khao Prabang Kram, Ko Talibong), Trang (Khao Chong, Tale Song Hong), Satun (Kuan Kalong, Terutao), Narathiwat (Waeng).

    D i s t r i b u t i o n.— Peninsular Thailand and Peninsular Malaysia (type).

    E c o l o g y.— Primary and secondary forest, evergreen Dipterocarp forest, bamboo forest, swampy forest, logged-over forest, along streams; on undulating country in shade of taller trees or in full sun; soil: limestone. Altitude: sea level up to 400 m.

    V e r n a c u l a r.— Chik nam (จิกน) (Satun); ta chai (ตาไชย) (Trang);  lao (เหลา) (Yala).

3. Agrostistachys indica Dalzell, Hooker's J. Bot. Kew Gard. Misc. 2: 41. 1850; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 103, Fig. 20c, d. 1912; Airy Shaw, Kew Bull. 14: 472. 1960; Kew Bull. 26: 210. 1972; Sevilla & Welzen, Blumea 46: 83, Map 4. 2001; Welzen & Sevilla in Chayam. & Welzen, Fl. Thailand 8, 1: 43. 2005.— Agrostistachys indica Dalzell subsp. genuina Müll.Arg. in DC., Prod. 15, 2: 726. 1866, nom. illeg.— Agrostistachys indica Dalzell subsp. longifolia Müll.Arg. in DC., Prod. 15, 2: 726. 1866.— Agrostistachys longifolia (Müll.Arg.) Kurz, Rep. Pegu: App. A cxi, App. B 79. 1875.— Agrostistachys maesoana Vidal, Rev. Pl. Vasc. Filip.: 242. 1886.— Agrostistachys indica Dalzell var. subintegra Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 105. 1912, nom. illeg.— Agrostistachys indica Dalzell var. maesoana (Vidal) Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vi: 105. 1912.— Heterocalyx laoticus Gagnep., Notul. Syst. 14: 33. 1950.

Shrubs or trees up to 5 m high. Stipules narrowly triangular, 4-17 by 2-4 mm, caducous, scars up to 5 cm below the leaves. Leaves: petiole 0.2-7 cm long; blade (narrowly) elliptic to obovate, 8-40 by 1.5-13 cm, length/width ratio 2.2-5.7, papery to subcoriaceous, margin dentate with teeth ending in glands, nerves 10-27 per side, drying yellowish. Inflorescences single to up to 6 superposed, up to 3 cm long, subsericeous. Bracts ovate, 2-6 by 2-5 mm. Flowers single per bract; sepals 2-5; petals 5(-9). Staminate flowers 3.5-5 by 3-4 mm; pedicel 4-6 mm long; sepals 3-4 by 2-3.5 mm; petals 2-5 by 1-2.5 mm; disc lobes 5-7(-10); stamens 13-16 in one whorl, basally united, 2.5-4 mm long; pistillode absent. Pistillate flowers 5-7 by c. 3 mm, purple; pedicel c. 4 mm long; sepals 3-5 by 1-2 mm; petals 2.5-3.5 by 1-1.5 mm; disc lobes 5(-10); ovary 0.5-1.5 by 1-1.7 mm; style c. 1 mm long; stigmas 1-1.5 mm long. Fruits 12-13 by 8-10 mm. Seeds 5-8 by 5-7 mm.

    T h a i l a n d.— PENINSULAR: Phangnga (Takua Pa, Thung Maphrao), Nakhon Si Thammarat (Kao Soen), Narathiwat (Waeng).

    D i s t r i b u t i o n.— India (type), Sri Lanka, Myanmar, Laos, Thailand, Vietnam, Borneo, Philippines, New Guinea.

    E c o l o g y.— Primary and secondary evergreen forest in undergrowth, along (dry) streams, on low hills and ridges, locally common; soil: clay, sand, rocky and boulder rich. Altitude: sea level up to 400 m.

    V e r n a c u l a r.— Hang kwang (หางกวาง) (Prachin Buri); plao (เปล้า) (Trang).