Flora of Thailand Euphorbiaceae

 

4. Alchornea

This page has been changed, in Alchornea rugosa no more varieties are recognised, and A. parviflora was wrongly identified as A. trewioides.

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Genus description

Identification key

Species descriptions

Alchornea

Sw., Prod. Veg. Ind. Occ. 98. 1788; Benth. & Hook.f., Gen. Pl. 3: 314. 1880; Airy Shaw, Kew Bull. 26: 211. 1972; G.L.Webster, Ann. Missouri Bot. Gard. 81: 81. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 192. 2001; Chanth. in Chayam. & Welzen, Fl. Thailand 8, 1: 45. 2005; Welzen & Bulalacao, Syst. Bot. 32: 804. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 112, Fig. 24. 2014.

Shrubs or small trees, usually dioecious.  Indumentum simple hairs.  Leaves simple, alternate; blade chartaceous or membranous, margin crenate or dentate, two distinct types: either blades obovate, penninerved, short-petioled, basal stipellae lacking, macular glands along total blade length above or beneath, or blades ovate, palmatinerved, long petioled, with 2 basal stipellae at insertion, sometimes bearing 2–4 basal macular glands.  Inflorescences simple or compound racemes or spikes, axillary, unisexual, either with groups of staminate flowers per node or a single pistillate flower; bract with a single to several flowers, basally usually biglandular.  Flowers lacking petals and disc.  Staminate flowers subsessile or wih short pedicel; sepals 2–5, valvate; stamens 8 (Thailand), connate on recepetacle annulus, anthers shortly oblong, opening introrsely, pistillode absent.  Pistillate flowers: sepals 4–8, sometimes 1–4 glandular, imbricate; ovary 3-locular, loculi 1-ovulate, style absent or minute; styles 3 undivided, recurved.  Fruits capsular, 3-lobed, smooth or verrucose, dehiscing septicidally and partly loculicidally into 2-valved cocci; column persistent. Seeds without caruncle.

    A genus of 70 species in the tropics, only 3 species in Thailand. Classification: Subfam. Acalyphoideae , tribe Alchorneae, subtribe Alchorneinae.

1. Alchornea parviflora (Benth.) Müll.Arg., Linneaa 34: 168. 1865; in DC., Prodr. 15, 2: 902. 1966; Merr., Enum. Philipp. Fl. Pl. 2: 348. 1923; Airy Shaw, Alphab. Enum. Euphorb. Philipp. Isl.: 3. 1983; Welzen & Bulalacao, Syst. Bot. 32: 807, fig. 1b, c, f; 2i-k; 3. 2007. — Stipellaria parviflora Benth., Hooker's J. Bot. Kew Gard. Misc. 6: 4. 1854. — Alchornea adenophylla Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii: 251. 1914; Ridl., Fl. Malay Penins. 3: 278. 1924; Whitmore, Tree Fl. Malaya 2: 54. 1973; Airy Shaw, Kew Bull. 36: 251. 1981. — Alchornea borneensis Pax & K.Hoffm., Mitt. Inst. Algg. Bot. Hamburg 7: 227. 1931; Airy Shaw, Kew Bull., Addit. Ser. 4: 28. 1975. — Alchornea trewioides aunct. non (Benth.) Müll.Arg.: Chanth. in Chayam. & Welzen, Fl. Thailand 8, 1: 47. 2005.

Shrub or small tree 1–5 m high, rather glabrous or slightly puberulous.  Stipules linear, c. 5 mm long, caducous.  Leaves: petiole 3–12.5 cm long glabrous or hairy; blade deltoid or ovate-orbicular, 5–14 by 4–9 cm, membranous, base obtuse or truncate, with 2 stipellae at insertion, latter linear, acuminat, c. 2 mm long, also with 1–3 macular glands, margin obscurely glandular toothed, apex abruptly acuminate; venation 3-nerved; nerves 3–5 pairs, not arching but joined near the margin, veins scalariform.  Inflorescences usually single spikes or racemes, up to 12 cm long; bracts elliptic, c. 1 mm long, margin hairy, caducous.  Flowers sessile to pedicelled.  Staminate flowers: sepals 2 or 3; stamens with short filaments, anthers c. 1 mm long.  Pistillate flowers: sepals 6–8 in 2 whorls, linear acuminate, apically villous; ovary ovoid, densely villous, style minute, stigmas 7–11 mm long, villous beneath.  Capsules globose, strongly lobed, up to 5 mm high, smooth, grey tomentellus.

    T h a i l a n d.— NORTH-EASTERN: Loei; EASTERN: Nakhon Ratchasima; SOUTH-WESTERN: Phetchaburi; PENINSULAR: Ranong Yala.

    D i s t r i b u t i o n.— Malay Peninsula, Sumatra, Borneo, and the Philippines.

    E c o l o g y.— In hill evergreen forest, some along stream at altitude 650–1300 m (mostly over altitude 1000 m).  Flowering from November to March.

    V e r n a c u l a r.— Khang khaeng khae (ขางแข้งแคระ) (Phitsanulok); Christmas Bush (China).

    N o t e.— This species was always mistaken for Alchornea trewioides. The latter only occurs in S. China.

2.  Alchornea rugosa (Lour.) Müll.Arg., Linnaea 34: 17. 1865; Craib, Bull. Misc. Inf. Kew: 465. 1911; Aberdeen Univ. Stud.: 57, 192. 1912; Pax & K.Hoffm. in Engl., Planzenr. IV.147.vii: 243. 1914; Gagnep. in Lecomte, Fl. Indo-Chine 5: 379. 1926; Airy Shaw, Kew Bull. 26. 211. 1972; Whitmore Tree Fl. Malaya 2: 53. 1973; Airy Shaw, Kew Bull. Add. Ser. 4: 28. 1975; Kew Bull. 31. 393. 1976; Kew Bull. 35: 593. 1980; Kew Bull. 36: 249. 1981; Kew Bull. 37: 4. 1982; Chanth. in Chayam. & Welzen, Fl. Thailand 8, 1: 45, fig. 9. 2005; Welzen & Bulalacao, Syst. Bot. 32: 804. 2007.— Cladodes rugosa Lour., Fl. Cochinch.: 574. 1790.— Conceveibum javanense Blume, Bijdr.: 614. 1825.— Adelia glandulosa Blanco, Fl. Filip.: 814. 1837.— Aparisthmium javense Endl. ex Hassk., Cat. Pl. Hort. Bogor. Alter: 235. 1844.— Tragia innocua Blanco, Fl. Filip., ed. 2: 479. 1845.— Alchornea javensis (Endl. ex Hassk.) Müll.Arg., Linnaea 34: 170. 1865 (non Backer & Bakh.f.); Hook.f., Fl. Ind. 5. 422. 1866; Ridl., Fl. Mal. Pen. 2. 278. 1924.— Alchornea hainanensis Pax & K.Hoff. in Engl., Planzenr. IV.147.vii. 242. 1914.— Alchornea javanensis (Blume) Backer & Bakh.f., Fl. Java 1. 485. 1963 (non Müll.Arg.).— Alchornea rugosa (Lour.) Müll.Arg. var. macrocarpa Airy Shaw, Kew Bull. 26: 211.1972. — Alchornea petalostyla Airy Shaw, Kew Bull. 35: 395. 1980.

Shrub or small tree, 1–6 m high, villous, glabrescent.  Stipules subulate, c. 10 mm long, persistent.  Leaves: petiole 5–35 mm long, with villous hairs; blade obovate, 9–20 by 4–7 cm, chartaceous or membranaceous, base narrowly obtuse to somewhat cordate, without stipellae at insertion, margin dentate-glandular, apex acuminate, upper or lower surface with a row of macular glands on each side, especially basally, glabrous or hairy, especially on the nerves and lower surface; nerves 5–7 pairs, always arching near the margin, veins scalariform, veinlets finely reticulate.  Inflorescences villous, paniculate when staminate, 2 or 3 racemes when pistillate; bracts elliptic, inconspicuous. Flowers subsessile to shortly pedicelled; pedicel villous.  Staminate flowers: sepals 2 or 3, ovate; stamens in 2 alternate rows, filaments basally forming ring.  Pistillate flowers: sepals 4, ovate, acuminate. Capsules small, minutely white puberulous. Seeds ovoid, compressed, shiny brown.

    T h a i l a n d.— NORTHERN: Chiang Rai, Lampang, Mae Sariang, LARSEN, SANTISUK & WARNCKE 2398, type, holo AAU, Phrae, Uttaradit, Tak, Sukhothai, Phitsanulok; NORTH-EASTERN: Phetchabun, Loei, Khon Kaen; EASTERN: Chaiyaphum, Roi Et; SOUTH-WESTERN: Uthai Thani, Phetchaburi, Prachuap Khiri Khan; CENTRAL: Chai Nat, Saraburi, Nakhon Nayok; SOUTH-EASTERN: Sa Kaeo, Prachin Buri, Chon Buri, Chantaburi; PENINSULAR: Chumphon, Surat Thani, Trang, Songkhla, Narathiwat..

    D i s t r i b u t i o n.— Burma, Nicobar Is. and throughout Malesia to New Guinea and Queensland (type: Indochina).

    E c o l o g y.— In evergreen or deciduous forest, in shady along stream up to 800 m.  Flowering in December to March.

    V e r n a c u l a r.— Kabuea ton (กระบือต้น), khang poi (ขางปอย), plao nam (เปล้าน้ำ) (Northern); khang ton diao (ขางต้นเดียว), niam kang (เนียมกาง) (North-eastern); dap yang (ดับยาง), kam pu (ก้ามปู), lap yang (ลับยาง) (Eastern); sabai bang (สะไบบาง) (South-eastern).

    U s e s.— The seeds are used as a purgative.  Leaves are boiled and drunk for stomach upset.

    N o t e.— At first we wanted to maintain variety macrocarpa. The type (N. Thailand) has indeed much larger fruits (12 by 10 mm versus 3—8 by 4—7 mm), large (but not larger) and elliptic leaf blades (14—30 by 6—13 cm versus 4—32 by 1.8—8.5 cm and generally obovate in common rugosa), and an acute blade base (instead of narrowly cordate). Also typical are the stigmas which have multiple frays at the end. Similar specimens, but with normal-sized fruits are present in S. Thailand (J.F. Maxwell 85-454, 87-443, 87-444) and N. Peninsular Malaysia (Stone et al. 15217) and in S. Peninsular Malaysia (Ahmad 278, Loh Hoy Shing KEP FRI 6867). This is a very disjunct distribution. However, the elliptic shape and cuneate leaf base are also found in Indian, Thai, and Vietnamese specimens, which further equal normal rugosa. Moreover, the ‘macrocarpa’ specimens from S. Thailand and Peninsular Malaysia are often (partly) slightly obovate. The multiple frayed stigmas occur very accidently within A. rugosa (e.g., former A. petalostyla). Thus, only the type specimen is really exceptional in its large fruits. As it is the only specimen showing this character we consider it to be an exceptional specimen rather than a good variety.

3.  Alchornea tiliifolia (Benth.) Müll.Arg., Linnaea 34: 168. 1865; Kurz, For. Fl. Br. Burm. 2: 386. 1877; Hook.f., Fl. Brit. Ind. 5: 421. 1877; Craib, Bull. Misc. Inf. Kew 466. 1911; Aberdeen Univ. Stud. 57. 192. 1912; Pax & K.Hoffm. in Engler, Planzenr. IV.147.vii: 250. 1914; Ridl., Fl. Mal. Pen. 3. 277. 1924; Gagnep, in Lecomte, Fl. Indo-Chine 5: 382. 1926; Airy Shaw in Kew Bull. 26: 212. 1972; Chanth. in Chayam. & Welzen, Fl. Thailand 8, 1: 47, fig. 10, plate III: 1. 2005.— Stipellaria tiliaefolia Benth., Hook., Kew Journ. 6: 4. 1854.— Stipellaria villosa Benth., Hooker’s J. Bot. Kew Gard. Misc. 6: 4. 1854. — Alchornea villosa (Benth.) Müll.Arg., Linnaea 34: 168. 1865; in DC., Prodr. 15, 2: 902. 1866.

Shrub or small tree 3–12 m high, rather densely hairy, glabrescent.  Stipules linear-acuminate, c. 7 mm long, caducous.  Leaves: petiole 5–10 cm long, villous; blade ovate to deltoid, 12–19 by 6.5–11 cm, base truncate or subcordate, with 2 stipellae at insertion, latter linear, 3–4 mm long, also with 1–3 macular glands, margin dentate glandular with short hairs, apex abruptly apiculate, glabrous above, puberulous on venation beneath; venation trinerved, nerves 4–6 pairs, not arching, ending near the margin, veinls scalariform, distinctly prominent beneath.  Inflorescences single to groups of racemes, villous, up to 10 cm long in fruit.  Flowers sessile or subsessile.  Staminate flowers with minute bracts; sepals 2 or 3, ovate; stamens with short filaments on ridge.  Pistillate flowers with linear, acuminate bracts; sepals 6, ovate, outer whorl 2–3 mm long; ovary ovoid, villous, minutely tubercled; style c. 1 mm long; stigmas 4–8 mm long, erec.  Capsules ovoid or globose, ca. 10 by 9 mm, finely verrucose beneath the middle, villous.  Seeds ridged, tuberculate.

    T h a i l a n d.— NORTHERN: Chiang Mai, Nan, Lampang, Phitsanulok; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Chantaburi; PENINSULAR: Chumphon, Ranong, Phangnga, Satun, Songkhla.

    D i s t r i b u t i o n.— E. Himalaya, Assam Burma, S. China, Indochina, Andamans, Malay Peninsula.

    E c o l o g y.— In shade in evergreen forest, sometimes near stream from altitude 500 m up to 1300 m.  Flowering nearly all years.

    V e r n a c u l a r.— Khang poi (ขางปอย) (General).