Flora of Thailand Euphorbiaceae

 

51. Koilodepas

 

P.C. van Welzen & K. Chayamarit

 

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Genus description

Identification key

Species descriptions

(often as ‘Coelodepas’) Hassk., Verslagen Meded. Afd. Natuurk. Kon. Akad. Wetensch. 4: 139. 1856; Flora 40: 531. 1857; Müll.Arg. in DC., Prodr. 15, 2: 759. 1866; Benth., Hook. Icon. Pl. 13: t. 1288. 1879; Gen. Pl. 3: 313. 1880; Hook.f., Fl. Br. Ind. 5: 419. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii: 268. 1914; Croizat, J. Arnold Arbor. 23: 50. 1942; Airy Shaw, Kew Bull. 14: 382. 1960; Kew Bull. 16: 354. 1960; Kew Bull. 26: 284. 1972; Whitmore, Tree Fl. Mal. 2: 103. 1973; Airy Shaw, Kew Bull. Add. Ser. 4: 137. 1975; Kew Bull. 36: 310. 1981; G.L.Webster, Ann. Missouri Bot. Gard. 81: 79. 1994; Radcl.-Sm., Gen. Euphorbiacearum: 180. 2001; Welzen & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 348. 2007; Welzen, Ann. Missouri Bot. Gard. 97: 222. 2010; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 136. 2014.— Calpigyne Blume, Ann. Mus. Bot. Lugduno-Batavum 2: 193. 1857.— Conceveiba Aubl. sect. Coelodepas (Hassk.) Kuntze in T.Post & Kuntze, Lex. Gen. Phan.: 138. 1903.— Nephrostylus Gagnep., Bull. Soc. Bot. France 72: 467. 1925.— Koilodepas Hassk. sect. Koilodepas: Airy Shaw, Kew Bull. 14: 383. 1960.— Koilodepas Hassk. sect. Hyalodepas Airy Shaw, Kew Bull. 14: 383. 1960.

Shrubs or small trees, monoecious (Thailand) or dioecious. Indumentum stellate hairs. Stipules often persistent, margin entire to pectinate. Leaves alternate, simple, petiolate, chartaceous to coriaceous, symmetric, margin entire to serrate, venation penninerved. Inflorescences axillary spikes (to panicles when with a few short branches), often several together, either unisexual with only dense groups of staminate flowers per node or only single pistillate flowers per node, or bisexual with groups of staminate flowers with usually a single pistillate flower (Thailand) per node; bracts subulate. Flowers (sub)sessile, calyx densely hairy outside, petals and disc absent. Staminate flowers: calyx lobes 3 or 4, valvate; stamens (3)4-7(-10), in a single whorl, filaments basally connate, broad strap-like, anthers subapically dorsifixed, 2-loculate, opening introrsely with horizontal slits; pistillode small, cone-like. Pistillate flowers: calyx cupular to urceolate, (4)5-10-lobed, lobes imbricate; ovary (2)3-locular, ovules 1 per locule, style short, stigmas entire to apically split to apically multifid or coralliform, apically long papillate, usually persistent. Fruits (2)3-lobed capsules, lobes globular, mainly in an (enlarged) persistent calyx, splitting into 3 bivalved cocci, wall thick, woody, outside tomentose, inside glabrous; columella persistent, broadly obtriangular. Seeds subglobose, glabrous, shiny, ecarunculate.

    A genus of c. ten species, from S. India to Hainan and throughout Malesia to New Guinea, most species in Southeast Asia and West Malesia; three species in Thailand. Classification: Subfam. Acalyphoideae, tribe Epiprineae, subtribe Epiprininae

Key to the species

1. Koilodepas bantamense Hassk., Verslagen Meded. Afd. Natuurk. Kon. Akad. Wetensch. 4: 140. 1855; Bot. Zeitung (Berlin) 14: 802. 1856; Flora 40: 532. 1857; Hort. bogor. descr. 1: 45. 1858; Miq., Fl. Ned. Ind. 1(2): 398. 1859; Müll.Arg. in DC., Prodr. 15, 2: 759. 1866) 759; J.J.Sm., Meded. Depart. Landb. Ned.-Indië 10: 380. 1910; S.Moore, J. Bot. 63, Suppl.: 101. 1925; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii: 269, fig. 42a—c. 1914; Airy Shaw, Kew Bull. 14: 384. 1960; Backer & Bakh.f., Fl. Java 1: 486. 1963; Airy Shaw, Kew Bull. 36: 311. 1981; Welzen, Ann. Missouri Bot. Gard. 97: 224, Fig. 1a, b, 2e, g. 2010.— Calpigyne frutescens Blume, Mus. Bot. 2: 193. 1857.—  Koilodepas wallichianum Benth., Hooker’s Icon. Pl. 13: t. 1288. 1879.—  Koilodepas ferrugineum Hook.f., Fl. Br. India 5: 420. 1887.—  Ptychopyxis frutescens (Blume) Croizat, J. Arnold Arb. 23: 49. 1942.—  Koilodepas frutescens (Blume) Airy Shaw, Kew Bull. 14: 385. 1960.

Shrubs to trees up to 27 m high, d.b.h. up to 50 cm, sometimes rheophytic when young; flowering branches 1.5—4 mm in diameter. Outer bark smooth, white to patchy grey and grey-green to grey-brown to honey-coloured, papery, sometimes flaking, soft; inner bark pink to reddish brown to brown, thin, brittle-fibrous; wood medium hard, sapwood cream to yellow, heartwood yellow to orange. Stipules triangular, 2—8 by 0.6—1.5 mm, margin often somewhat erose or with at most one or two upright teeth, mainly on one side.  Leaves: petiole 3—16 mm long, round to flattened above; blade ovate-oblong to elliptic-oblong, 5.8—33 by 1.7—11.2 cm, length/width ratio 2.7—5.3, drying (greenish to) brownish, base truncate to cuneate, margin coarsely serrulate (to entire), flat to slightly recurved, teeth ending in a glandular region; apex acute to cuspidate; upper surface dull dark green; lower surface dull green, glabrous to hairy on basal part of the midrib, nerves 11—15 per side, often somewhat bullate between nerves. Inflorescences up to 10.5 cm long, yellowish green to pale brown. Flowers whitish in bud to grey-yellow when dehisced. Staminate flowers 1.2—2.4 mm in diameter; bracts triangular, 1.1—2.2 by 1.1—3.5 mm, sometimes margin with teeth, at base often with extrafloral nectaries; pedicels 0.2—0.9 mm long; calyx 1—1.2 mm high, 3- or 4-lobed, lobes triangular, 0.7—1.2 by 0.8—1.4 mm; stamens 4 or 5, androphore 0.7—0.8 mm high, filaments 0.7—1 mm long, sulcate, anthers 0.2—0.3 by 0.3—0.5 mm, yellow; pistillode absent to c. 0.2 mm long. Pistillate flowers 2.5—3.5 mm in diameter; bracts triangular, 2—7 by 1.2—2.3 mm, margin often with round extrafloral nectaries, often united with the bracteoles; bracteoles similar, much smaller, 1.8—2.5 by 0.6—1.8 mm; pedicel 0.7—1.8(—22 in fruit) mm; calyx tightly urceolate and adnate to ovary, 2—3.3 mm high, 7- or 8-lobed, lobes inconspicuous, outside usually extrafloral nectaries on tube, splitting into (horizontal to) reflexed lobes, in fruit not much increasing in size, up to 3(—5) mm long; ovary 3-locular, 2—3 by 1.5—2.7 mm, style 0—0.3 mm long, stigmas 1.5—2.5 mm long, yellow, deeply bilobed, each lobe split several times, spreading fan-like, very compact, individual stigmas not visible. Fruits lobed rhegmas, 16—18 by 8—11 mm, yellowish green when young, to orange, brown hairy; wall c. 1.2 mm thick; columella 6—10 by 4.5—7.3 mm. Seeds 7—8.5 by 7.2—9 by 6—8.2 mm.

    T h a i l a n d.— SOUTH-WESTERN: Phetchaburi (Kaeng Krachan National Park), Prachuap Khiri Khan (Huay Yang National Park); PENINSULAR: Ranong, Phangnga (Ko Surin Nua), Nakhon Si Thammarat (Chawang), Songkhla (Ko Hong), Trang.

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

    E c o l o g y.— Primary dry evergreen forest (Thailand) and primary rain foreset, sometimes also secondary forest, scrubs and overgrown rubber plantations; soil yellow-red loam; bedrock granite or sandstone. Altitude: 50—400 m. Flowering: January to August; fruiting: May and June, October and November.

    U s e s.— The wood is used for wood carving, knife handles and sheaths.

    N o t e.— This is a variable species and unfortunately very much alike K. longifolium and K. hainanense. All three species have generally elliptic-oblong leaves with an entire up to coarsely serrulate margin. Koilodepas bantamense has pistillate flowers with a narrowly urceolate calyx (with or without glands), which do not enlarge in fruit. The stigmas are short and branch into broad fans. The stipules generally have an entire margin or have one or two teeth. Koilodepas hainanense (incl. Nephrostylus poilane) differs in the pistillate flowers with calyces that enlarge in fruit, in flower the calyces are not narrowly enclosing the ovary, but somewhat folded around the ovary; the stipules also show more teeth. The calyx of the pistillate flowers of Koilodepas longifolium reaches till halfway the ovary and slightly enlarges in fruit, the stigmas are less branched and generally have a longer unbranched basal part; the stipules usually have upwards bent teeth. Koilodepas hainanense only slightly overlaps in SW Thailand with K. bantamense. However, the other two species largely overlap in distribution. Luckily, there is one more chacarter that generally separates the two species, K. longifolium has very small glands on the marginal teeth of the leaf blade, while K. bantamense generally has glands that broadly cover the rounded apex of the teeth.

2. Koilodepas hainanense (Merr.) Croizat, J. Arnold Arb. 23: 51, p.p., excl. Nephrostylus poilanei Gagnep. 1952; Airy Shaw, Kew Bull. 14: 384. 1960; Kew Bull. 36: 311. 1981.—  Calpigyne hainanensis Merr., J. Arnold Arb. 6: 135. 30 July 1925.— Nephrostylus poilanei Gagnep., Bull. Soc. Bot. France 72: 467. Aug. 1925.

Tree(let)s, up to 15 m high, d.b.h. up to 4 cm; flowering branches 1.5—2.3 mm thick. Bark smooth, grey-brown. Stipules triangular, 3.5—8 by 1—1.5 mm, margin slightly erose, with some short teeth, up to 1 mm long, glands absent. Leaves: petiole 0.5—1.2 mm long, somewhat flattened above; blade (ovate to) elliptic-oblong (to obovate), 6.5—22.5 by 2.1—7.5 cm, length/width ratio 3—3.5, drying brownish to sometimes greenish, base obtuse to rounded, flat, margin finely serrulate with glandular teeth to (secondarily) almost entire, flat, apex acuminate, upper surface dark green, lower surface slightly hairy on major venation, not much paler than above, nerves 10—18 per side. Inflorescences up to more than 10 cm long. Flowers lemon-yellow, strongly fragrant, but little agreeable. Staminate flowers 1—1.5 mm in diameter; bracts ovate to triangular, c. 1.7 by 2.2 mm, margin entire, glands absent; pedicels 0.1—0.4 mm long; calyx 1—1.2 mm high, with 3 or 4 lobes, latter 0.7—1 by c. 0.7 mm; stamens 4 or 6, androphore c. 0.3 mm long, filaments c. 0.6 mm long, sulcate, anthers c. 0.3 by 0.6 mm, yellow; pistillode c. 0.3 mm long, broad. Pistillate flowers 2.5—4.8 mm in diameter; bracts long triangular, 5—5.3 by c. 1 mm; bracteoles broad triangular, 2—3.5 by 1.2—1.8 mm, both withmargin entire to glandular toothed; pedicels short to up to 18 mm in fruit; calyx basally united, up to 3.5 mm high (enlarging in fruit to c. 19 mm high), lobes 8—10, indistinct (enlarging in fruit to 18 by 6 mm), folded around ovary, with extrafloral nectaries in mainly the united part; ovary 3-locular, c. 2 by 1.5—2 mm, style absent, stigmas 2—3.2 mm long, flat and spreading, top broad and hardly split to split into two major branches and each branch split several times less deep, fan-like, individual stigmas not visible. Fruits lobed rhegmas, 12—15 by 10—11 mm, green with orange tinge to brown-green; wall c. 0.8 mm thick; columella 6—8 by 5—7 mm. Seeds c. 6 by 6 by 5 mm.

    T h a i l a n d.— NORTH-EASTERN: Nong Khai (Phu Tok Noi, Phuwua Wildlife Sanctuary), Udon Thani (Nong Saeng).

    D i s t r i b u t i o n.— China (Hainan), N Vietnam.

    E c o l o g y.— Locally fairly common in (disturbed) primary evergreen forest, often on rocky shores of streams; soil sand, bedrock granite. Altitude: sea level up to 320 m. Flowering: March, June; fruiting: March—May, August.

Koilodepas longifolium Hook.f., Fl. Brit. Ind. 5: 420. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii: 270. 1914; Ridl., Fl. Mal. Pen. 3: 275. 1924; Airy Shaw, Kew Bull. 14: 388. 1960 Kew Bull. 26: 284. 1972; Whitmore, Tree Fl. Mal. 2: 104. 1973; Airy Shaw, Kew Bull. Add. Ser. 4: 139. 1975; Kew Bull. 36: 311. 1981; Radcl.-Sm., Gen. Euphorb.: 180, Fig. 22. 2001; Welzen & Chayam. in Welzen & Chayam., Fl. Thailand 8, 2: 349, Fig. 12. 2007; Welzen, Ann. Missouri Bot. Gard. 97: 231, Fig. 1d, h, 2a, 3a-f. 2010.— Coelodepas gladuligerum Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii: 270, Fig. 42d. 1914.— Coelodepas subcordatus Gage, Rec. Bot. Surv. India 9: 239. 1922, pro parte, quoad Curtis 1374 tantum.—  Koilodepas longifolium Hook.f. var. longifolium: Airy Shaw, Kew Bull. 14: 388. 1960.

Small trees up to 12 m high, bole up to 18 cm thick; flowering branches 1.5—2.3 mm in diameter. Outer bark white to light brown, smooth, slightly papery; inner bark pink, thin; wood yellow. Stipules triangular, 3.7—8 by 1—1.2 mm, late caducous, margin (entire to somewhat erose or) with several upright teeth, basal glands absent. Leaves: petiole 3—20 mm long, round; blade elliptic to elliptic-oblong, 8.5—27 by 2.7—8.2 cm, length/width ratio 3.1—3.2, drying brownish, base rounded to cuneate, margin (entire to) coarsely serrulate, flat to slightly recurved, teeth ending in a small and narrow gland, apex acuminate to cuspidate, sometimes mucronulate, upper surface mid green to very dark green, shiny; lower surface glabrous to hairy along midrib and basal nerves (Borneo), (slightly) paler green, nerves 9—15 per side, sometimes somewhat bullate between nerves. Inflorescences up to 12 cm long, dark yellow, witch brooms sometimes present, dark brown hairy, branching, flowers consisting of calyx cups, each with a short spike of bracts in it. Flowers pale green with a silvery tinge to cream to yellow. Staminate flowers 0.8—1.3 mm in diameter; bracts broadly ovate, 0.7—1.8 by 1—2 mm wide, sometimes split or margin erose, the basal part of the margin sometimes with round extrafloral nectaries; pedicels 0.2—0.8 mm long; calyx with 3 or 4 lobes, lobes entire or bilobed, sometimes split and seemingly 3 or 4 sepals, 0.9—1.2 mm high, teeth triangular, 0.5—0.6 by 0.4—0.8 mm, all acute; stamens 4 or 5 (or 6), androphore 0.2—0.4 mm high, filaments 0.5—0.6 mm long, sulcate, anthers c. 0.3 by 0.4 mm; pistillode absent to 0.4 mm long. Pistillate flowers 1.7—3 mm in diameter; bracts triangular 2.5—4.7 by 0.7—1 mm, sometimes glandular, margin often erose; bracteoles similar, 1.2—2.5 by 0.4—0.9 mm; pedicel 0.8—2.3(—11 in fruit) mm; calyx till halfway ovary, 0.6—2 mm high, 6—12-lobed, lobes triangular, 0.6—1 by 0.4—0.8 mm, outside usually extrafloral nectaries on tube; ovary (2)3-locular, 1.7—2 by 1.8—2 mm, style 0—0.8 mm long, stigmas 1.5—2.1 mm long, deeply bilobed till upper 1—2.2 mm, each lobe split somewhat, stigmas individually visible. Fruits lobed rhegmas, 12—14 by 8.5—10 mm, dark yellow to brownish; wall 0.8—1 mm thick; calyx reflexed, not increasing in size; columella broadly obtriangular, 6—6.5 by 4—6 mm long, basally few caducous stellate hairs. Seeds 6.5—7 by 7.5—7 by 5.2—6 mm.

    T h a i l a n d.— SOUTH-EASTERN: Trat (Hat Sai Daeng, Ko Chang, Tham Mayom Waterfall); PENINSULAR: Ranong, Surat Thani, Phuket (Ko Libong), Krabi, Nakhon Si Thammarat (Chawang), Trang (Kho Pup Pha), Songkhla (Ko Hong Hill), Pattani.

    D i s t r i b u t i o n.— Malay Peninsula (incl. Singapore), Sumatra (Riau Prov., Bangka Island), Borneo (Sabah, Brunei, Sarawak).

    E c o l o g y.— Primary mixed lowland dipterocarp forest and kerangas forest; soil: Sandstone, diorite scree, granitic sand, sandy clay, clay loam. Altitude: 6—330 m. Flowering: January to October, December; fruiting: January, June, July, September. Small black ants in “earth” nests among fruits.

    V e r n a c u l a r.— Ka raeng hin (กาแร้งหิน) (Chumphon); Chi mut (จีมุด) (Trang); Yan hang yong (ย่านหางโยง) (Surat Thani).