Flora of Thailand Euphorbiaceae

 

2. Actephila

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Genus description

Identification key

Species descriptions

Actephila

Blume, Bijdr. Fl. Ned. Ind.: 581. 1825; Benth., Gen. Pl. 3:269. 1880; Pax & K.Hoffm. in Engl., Pflanzenr. VI.147.xv: 191. 1922; Backer & Bakh.f., Fl. Java 1: 470. 1963; Airy Shaw, Kew Bull. 25: 496. 1971; Whitmore, Tree Fl. Malaya 2: 51. 1973; Airy Shaw, Kew Bull. 26: 208. 1972; Kew Bull. Add. Ser. 8: 21. 1980; G.L.Webster, Ann. Missouri Bot. Gard. 81: 37. 1994; Radcl.-Sm., Gen. Euphorb.: 10. 2001; Chayamarit in Chayamarit & Welzen, Fl. Thailand 8, 1: 35. 2005.— Lithoxylon Endl., Gen.: 1122. 1840.— Anomospermum Dalzell, Hook. J. Bot. Kew Gard. Misc. 3: 228. 1851 (non Miers, 1851).— Savia Willd. sect. Actephila (Blume) Baill., Étude Euphorb.: 571. 1858.

Trees or shrubs; monoecious.  Indumentum simple hairs, usually subglabrous.  Stipules caducous.  Leaves alternate, long or short-petioled; blade chartaceous or coriaceous, margin entire, penninerved.  Inflorescences usually solitary (or fascicled), axillary or extra-axillary, when fascicled on short raceme with few pistillate flowers at base, upwards only with staminate ones.  Flowers: sepals 5, subequal, imbricate; petals 5, shorter than sepals; disk a large, 5-lobed ring.  Staminate flowers: pedicel very short; stamens 3–6, filaments free or basally connate, on the disc; anther-cells parallel; pistillode 3-lobed.  Pistillate flowers: pedicel very long; calyx often persistent and enlarged in fruit; ovary 3-locular; ovules 2 per locule; style short, stigmas 2-fid at apex, persistent.  Fruits capsules, loculicidally (and partly septicidally) dehiscent.  Seeds large, without aril or caruncle; trigonous, almost without albumen.

    An Asian/Australian genus of ca. 20 species. 4 species in Thailand.  Classification: Subfam. Phyllanthoideae, tribe Wielandieae.

Key to the species

1.  Actephila collinsae Hunter, Misc. Inf. Kew Bull. 1924: 96. 1924; Gagnep. in M.H.Lecomte, Fl. Indo-Chine 5: 537. 1927; Smitinand, Nat. Hist. Bull. Siam Soc. 20: 139. 1962 Airy Shaw, Kew Bull. 26: 208. 1972; Chayamarit in Chayamarit & Welzen, Fl. Thailand 8, 1: 36, fig. 4. 2005.— Actephila siamensis Pierre ex Gagnep.: 531; Smitinand Nat. Hist. Bull. Siam Soc 20: 140. 1962.

Shrub, 1–2 m high; branches sparsely pilose, angular, light brown when young, soon glabrous, terete and greyish, lenticellate.  Stipule c. 2 mm long.  Leaves: pseudo-verticillate, crowded at the end of branches; petiole 3–6 mm long; blade oblanceolate, elliptic or obovate, 8–15.5 by 2.5–5 cm, coriaceous, base cuneate, apex usually obtuse, sometimes bluntly acute, glaucous or glaucescent beneath; nerves 10–12 pairs, inconspicuous on both surfaces, finely reticulation.  Staminate flowers: pedicels c. 5 mm long; sepals ovate-lanceolate, ovate or oblong-lanceolate, c. 5 by 2.5 mm wide, sparsely hairy outside, apex obtuse, entire; petals c. 0.5 mm long, pale yellow; disc entire; stamens free, anthers more or less globose. Pistillate flowers: solitary; pedicels 1.5–4 cm long, glabrescent on the upper, gradually thickened; sepals ovate to elliptic, c. 6 by 5 mm wide, apex rounded or obtuse, glabrous, enlarged in fruit, 9-veined; disc annular; ovary velutinous; stigmas c. 3 mm long.  Fruit c. 2 by 1.5 cm high, sepals accressent to 12 by 8 mm wide, greenish.  Seed 1.

    T h a i l a n d.— SOUTH-WESTERN: Uthai Thani (Lan Sak), Phetchaburi (Winit 552-type, BK, BKF); Prachuap Khiri Khan (Sam Roi Yot National Park).

    D i s t r i b u t i o n.— Endemic.

    E c o l o g y.— On dry limestone hills; alt. 100–300 m.  Flowering: March; fruiting: August.

    V e r n a c u l a r.— Si som (สีส้ม) (Phetchaburi).

    N o t e s.— This species is very distinct in the accrescent fruiting sepals and the glaucous or glaucescent on the lower sides of the leaves.  It is different from A. ovalis by the leaves not acuminate, nerves inconspicuous, stigmas free (style absent).

2.  Actephila excelsa (Dalzell) Müll.Arg., Linnaea 32: 78. 1863; in DC., Prodr: 15, 2: 222. 1866; Hook.f., Fl. Brit. Ind. 5: 282. 1887; Pax & K.Hoffm.in Engl., Pflanzenr. VI.147.xv: 191. 1922; Ridl., Fl. Mal. Pen. 3: 196. 1924; Gagnep in M.H.Lecomte, Fl. Indo-Chine 5: 535. 1927; Henderson, J. Mal. Br. Roy. As. Soc. 17: 68. 1939; Backer & Bakh.f., Fl. Java 1: 470. 1963; Airy Shaw, Kew Bull. 26: 209. 1972; Whitmore, Tree Fl. Mal. 2: 52. 1976; Chayamarit in Chayamarit & Welzen, Fl. Thailand 8, 1: 36, fig. 5. 2005.— Anomospermum excelsum Dalzell, Hook. J. Bot. & Kew Garden Misc. 3: 228. 1851.

Shrubs or small trees, 1–3 m high.  Leaves: petioles 2–10 mm long, rugose; blade elliptic, oblanceolate or obovate, 7–10 by 2.5–4 cm, chartaceous to subcoriaceous, base cuneate, apex acuminate, rarely obtuse, dark green above, pale green below; nerves 6–12 pairs, conspicuous below, reddish brown or yellowish brown, shiny. Inflorescences of solitary or fascicled flowers; bracts broadly ovate.  Flowers light pinkish brown or green; sepals 5 or 6; disc 5-lobed. Staminate flowers: pedicel up to 2 mm long, pendulous; sepals oblong-ovate or broadly lanceolate, 2.5–4 by c. 1 mm, puberulous; petals narrowly spathulate; disc crenulate;. stamens c. 2 mm long, filaments connate or free.  Pistillate flowers larger than staminate flowers; pedicel up to 4(–6.5 in fruit) cm long, thickened towards apex; calyx-lobes oblong(-triangular), up to 7 mm by 2.25 mm, inside at base with transverse row of minute pellucid appendages; petals spathulate-rhomboid, c. 1.5 by 1 mm, white; ovary subglobose, glabrous.  Fruit subglobose, 3-lobed, 1–1.5 by 1–2.5 cm, brownish green or green, turning dull dark reddish, columella c. 4 mm long.  Seeds 1–1.25 cm long.

    T h a i l a n d.— NORTHERN: Chiang Mai (Doi Inthanon, Doi Chiang Dao), Chiang Rai (Doi Tung); PENINSULAR: Surat Thani (Khao Wong, Klong Phanom National Park)

    D i s t r i b u t i o n.— Western Peninsular India, Assam and Burma.

    E c o l o g y.— In evergreen forest, montane forest, on rocky limestone hills; alt. to 1200 m.

3.  Actephila javanica Miq., Fl. Ind. Bat. 1: 359. 1859; Hook.f., Fl. Brit. Ind. 5: 283. 1887; Ridl., Fl. Mal. Pen. 3: 196. 1924; Airy Shaw, Kew Bull. Add. Ser. 8: 22. 1980; Chayamarit in Chayamarit & Welzen, Fl. Thailand 8, 1: 38, fig. 6. 2005.— Actephila excelsa (Dalzell) Müll.Arg. var. javanica (Miq.) Pax & K.Hoffm. in Engl., Pflanzenr. VI.147.xv: 192. 1922; Airy Shaw, Kew Bull. 26: 209. 1972; Whitmore, Tree Fl. Malaya 2: 52. 1976— Actephila excelsa (Dalzell) Müll.Arg. var. acuminata Airy Shaw, Kew Bull. 26: 209. 1971; Whitmore, Tree Fl. Malaya 2: 52. 1976.

Shrubs or small trees, 2–5 m high.  Leaves: petioles 1.2–7 cm long, puberulous, apex and base rugose and dark; sometimes pulvinate at apex; blade ovate to obovate, oblanceolate or oblong, 9–30 by 4–12.5 cm; chartaceous to coriaceous, base obtuse or cuneate, apex acuminate to caudate, dark green above, paler beneath; nerves 9–10 pairs, arched and looped at margin, conspicuous on both surfaces.  Inflorescences solitary or fascicled; bracts 4-seriate.  Staminate flowers: pedicels up to 2 mm long; sepals oblong, c. 2.5 by 1 mm; petals spathulate, c. 2 by 1.25 mm, pale green; stamens c. 2 mm long.  Pistillate flowers larger than staminate ones; pedicels up to 2 mm long (up to 3.5 cm in fruit, apex thickened); sepals oblong(-triangular), c. 7 by 2.25 mm; petals spathulate-rhomboid, c. 1.5 by 1 mm, white; ovary trigonous-globose.  Fruit 3-lobed, subglobose, c. 1 by 2.5 cm, green or dark green. Seeds 1–1.25 cm long.

    T h a i l a n d.— SOUTH-EASTERN: Chanthaburi (Makham, PENINSULAR: Ranong (Klong Nakha Wildlife Sanctuary, Ngao Waterfalls), Surat Thani (Khao Sok), Phuket, Krabi (Ko Phi Phi), Nakhon Si Thammarat (Garon Waterfalls, Chwang), Patthalung (Khao Pu Khao Ya), Trang (Khao Chong), Satun (Tarutao National Park), Songkhla (Khao Chum Sak at Hat Yai).

    D i s t r i b u t i o n.— India, Malaya, Sumatra (type), Borneo, Java.

    E c o l o g y.— In moist evergreen forest, along streams, on limestone hills; alt. 50–200 m.  Fruiting: August to October.

4.  Actephila ovalis (Ridl.) Gage, Rec. Bot. Surv. Ind. 9: 219. 1922; Ridl., Fl. Mal. Pen. 3: 196. 1924; Gage, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 75: 519. 1936; Henderson, J. Mal. Br. Roy. Asiat. Soc. 17: 68. 1939; Smitinand, Nat. Hist. Bull. Siam Soc. 20: 139. 1962; Airy Shaw, Kew Bull. 26: 210. 1972; Whitmore, Tree Fl. Mal. 2: 51. 1973; Chayamarit in Chayamarit & Welzen, Fl. Thailand 8, 1: 38, fig. 7, plate II: 1. 2005. —Dimorphocalyx ovalis Ridl., J. Roy. As. Soc. Str. Br. 59: 178. 1911.

Small trees or shrubs, 0.5–2 m high, puberulous, glabrescent.  Stipules ovate.  Leaves opposite or more or less whorled at the end of branches; petioles 0.3–1.2 mm long, hairy; blade lanceolate, elliptic, rarely obovate, 8–20.5 by 2–5 cm, subcoriaceous, base cuneate, margin undulate, apex acuminate to long acuminate, dark green above, green below; veins 10–14 pairs, looped near margins, inconspicuous on both surfaces, midrib sunken on the upper surface, raised below, reddish brown, shining.  Inflorescences axillary or on old branches, bracts ovate.  Flowers few, greenish. Staminate flowers: sepals whitish-cream or greenish, disc and filaments whitish, anthers yellow; ovary pale yellow.  Pistillate flowers: solitary; pedicels up to 6 cm long in fruit; sepals ovate, c. 2 by 1 cm, obtuse, yellowish green; ovary conical, pubescent, style absent, stigmas free.  Fruits  light yellow or green, turning black, with enlarged persistent calyx, sepals suborbicular or broadly elliptic or ovoid, 1–2.3 by 1–1.5 cm, 5–7 veins from the base, reticulation distinct.

    T h a i l a n d.— SOUTH-WESTERN: Prachuap Khiri Khan (Bang Saphan); SOUTH-EASTERN: Sa Kaeo (Pang Sida National Park); PENINSULAR: Surat Thani (Ko Tao), Pangnga (Khao Tham Thong Lang, Tap Put, Similan National Park), Krabi (Ban Nini Shong, Aoluk), Nakhon Si Thammarat (Khao Luang, Khiri Wong, Karom Waterfalls), Phatthalung (Khao Pu-Khao Ya National Park), Trang (Khao Chong), Satun (Kuan Sato, Talebun).

    D i s t r i b u t i o n.— North Malaya (Langkawi, Perlis, Kedah and Penang) (type).

    E c o l o g y.— Moist evergreen forest, common on  limestone hill; alt. 100–200  m.  Flowering: February to May; fruiting: May to July.

    N o t e s.— Differs from the more northerly A. collinsae in the green undersurface of the leaves and usually larger and thinner fruiting sepals. The distribution of the two do not appear to overlap.