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Malesian Euphorbiaceae Descriptions |
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Welzen, P.C. van, L.J. Bulalacao & Tran Van On. 1995. A taxonomic revision of the Malesian genus Trigonopleura Hook.f. (Euphorbiaceae). Blumea 40: 363–374.
Welzen, P.C. van & H.-J. Esser. 2013. Peraceae. In: Nooteboom, H.N. & van Welzen, P.C. (eds.), Flora Malesiana ser. 1, 21: 119–133.
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Trigonopleura Hook.f., Fl. Brit. India 5 (1887) 399; Pax in Engl. & Prantl, Pflanzenfam. III, 5 (1890) 84; Pax & K.Hoffm. in Engl., Pflanzenr. IV, 147, iii (1911) 95; xiv Euph.-Add. 6 (1919) 42; Whitmore, Tree Fl. Malaya 2 (1973) 134; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 201; Kew Bull. 36 (1981) 350; Alphab. Enum. Euph. Philipp. Isl. (1983) 46; Welzen, Bulalacao & On, Blumea 40 (1995) 368; Radcl.-Sm., Gen. Euphorbiacearum (2001) 115; Welzen & Esser in Noot. & Welzen, Fl. Males. ser. 1, 21 (2013) 127; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 103. — Type: Trigonopleura malayana Hook.f.
Peniculifera Ridl. (Sterculiaceae), J. Roy. As. Soc. Str. Br. 82 (1920) 173; Fl. Mal. Penin. 1 (1922) 290. — Type: Peniculifera penangensis Ridl. [= Trigonopleura malayana Hook.f.]
Trees, dioecious. Indumentum consisting of simple and stellately bundled, tomentose to hirsute hairs, latter deciduous. Stipules falcate, early caducous, tomentose. Leaves simple, distichous; petiole not to completely slightly pulvinate, below with transverse grooves when dry; blade symmetric (to slightly asymmetric), coriaceous, punctate; base emarginate to attenuate; margin entire; apex acuminate to caudate, very apex obtuse; both surfaces smooth, lower surface variously hirsute to glabrous; venation pinnate, at most slightly raised above, distinct below, nerves looped and joined at the margin, tertiairy nerves slgithly scalariform, veinlets reticulate. Inflorescences dense axillary clusters of 2 to many flowers (reduced thyrses), tomentose, brachyblasts increasing in size with age. Bracts on brachyblasts minute, triangular, hirsute. Pedicels with abscission zone, tomentose. Flowers actinomorphic. Sepals 5, imbricate, succulent, margin entire, apex (emarginate to) acute, outside keeled, tomentose, inside subglabrous. Petals valvate, more or less clawed, margin entire, apex emarginate to rounded, especially inside long hirsute. Disc annular, consisting of 5 lobes, obovate to square, more or less triangular in transverse section, thick, glabrous, orange. Stamens absent in pistillate flowers; in staminate flowers with a hirsute androphore from which the filaments branch in two bundles, a lower with 5 anthers and an upper with 3, between the upper a 3-lobed pistillode; anthers basidorsally fixed, opening latero-extrors with a slit; connective hirsute outside, apically often elongated into an appendix. Pistil in pistillate flower: ovary (seldom 2- or) 3-locular, tomentose; ovules one per locule, descending, epitropous, anatropous, attached halfway to column; style 1, short, hirsute; stigmas 3, deeply divided, above with dendritic papillae, on lower surface hirsute. Fruit a globose rhegma, outside densely tomentose, reticulately wrinkled when dry, with 6 raised lines, along which the septicidal dehiscence into 3 bifid pieces; inside smooth, glabrous; wall thin, woody. Seeds ovoid, flattened, 1–3 per fruit, black, glossy, abaxially covered up to 2/3rd by a thin, sometimes lobed aril, lobes sometimes touching adaxially; hilum v-shaped. Embryo ovoid, flattened, endosperm scanty.
Distribution — The genus comprises 3 species, all found in Malesia. One is widespread in W Malesia (Peninsular Malaysia, Sumatra, Borneo, Sulawesi; not known from Singapore), the others are endemics in Sarawak or in the Philippines.
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1a. |
Fruits 1.4–2.1 cm wide by 1.5–1.7 cm high, wall 2.5–4.3 mm thick. Flowers 5–7 by 4–8 mm diam. Aril also covering seed adaxially up to 1/2–2/3rd in the Philippines — Sarawak, Philippines |
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1b. |
Fruits 0.9–1.3 cm wide by 1–1.3 cm high, wall 1.5–2.3 mm thick. Flowers 5–6 by 4–7 mm diam. Aril adaxially at most only basally covering seed — Malaya, Sumatra, Borneo |
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Leaves 7.3–21.5 by 3.8–7.1 cm, margin flat, subglabrous below (microscope!), brown when dry. Fruit wall c. 2.5 mm thick — Philippines |
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2b. |
Leaves 5.7–14 by 2.5–5.5 cm, margin revolute, glabrous below, blackish brown when dry. Fruit wall c. 4.3 mm thick — Sarawak |
Trigonopleura dubia (Elmer) Merr., Philipp. J. Sc. Bot. 11 (1916) 77; Pax & K.Hoffm. in Engl., Pflanzenr. IV, 147, xiv Euph.-Add. 6 (1919) 42; Welzen, Bulalacao & On, Blumea 40 (1995) 369, Fig. 2b, c; Map 1; Welzen & Esser in Noot. & Welzen, Fl. Males. ser. 1, 21 (2013) 129, fig. 2b, c; map 2. — Alsodeia dubia Elmer (Violaceae), Leafl. Philipp. Bot. 8 (March 1915) 2875. — Type: Elmer 13956 (PNH, holo, †; iso in L, NSW), Philippines, Mindanao, Agusan Prov., Cabadbaran (Mt. Urdaneta).
Trigonopleura philippinensis Merr., Philipp. J. Sc. Bot. 10 (July 1915) 275. — Type: BS (Ramos) 17475 (PNH, holo, †; iso in K, L), Philippines, Samar.
Trigonopleura malayana auct. non Hook.f.: Airy Shaw, Alphab. Enum. Euph. Philipp. Isl. (1983) 46.
Tree, up to 25 m high, d.b.h. up to 90 cm; flowering branches 3.5–5 mm thick, ribbed to smooth, hirsute when young, descending. Bark: outer red or brown on trunk to grey on branches, smooth, c. 2 mm thick; inner reddish brown, c. 0.5 cm thick. Wood soft to hard, odourless, slightly bitter; sapwood thin, white tinged reddish. Leaves descending; stipules obovate, c. 7 by 2.5 mm; petiole 5–13 mm long, laterally flattened and deeply keeled on upper side with the walls touching, leaving a closed groove; blade ovate to obovate, 7.3–21.5 by 3.8–7.1 cm, index 2.5–3.2, darker green above, brown when dry, margin flat, apex ascending, upper surface glabrous (except for the basal part of the midrib); lower surface subglabrous, nerves 8–11 per side. Bracts on brachyblasts c. 0.7 by 0.7 mm. Flowers 5–7 by 4–8 mm in diam., odourless, ascending; pistillate flowers not seen. Pedicels 9–10 mm long; upper part above abscission zone 3–4 mm long. Sepals elliptic to obovate, 3.8–5 by 2.2–3 mm, green. Petals elliptic to obovate, 4–5.2 by 1.2–2 mm in staminate flowers, cream white. Disc lobes 0.9–1.4 by 0.7–0.9 mm. Stamens in staminate flowers: androphore 4–5.5 mm long; filament 1–1.3 mm long, cream white; anther ± triangular, 0.8–1.1 by 0.7–0.9 mm, dull yellow. Pistil in pistillate flower not seen. Fruit 1.4–1.6 by 1.5–1.7 cm high, red to purple; wall c. 2.5 mm thick. Seeds 5.8–7.5 by 5.3–6.5 mm; aril covering seed also adaxially, pink; hilum 2.8–4 mm broad. Embryo 6–6.5 by 5.5–6 mm; aril also adaxially closing; plumule and radicle not seen.
Distribution — Malesia: Endemic in the central E Philippines (Samar and Leyte up to NE Mindanao).
(dots in Philippines; square = T. macrocarpa).
Ecology and Habitat — Found in primary Dipterocarp forest to logged over forest, on shady to open places like streams and forest margins. Alt.: 200–1250 m. Flowering: March, April, (Septmber); fruiting: March to July.
Vernacular name — Badabogan (Manobo lang.).
Note — Typical for T. dubia, just like for T. macrocarpa, are the flowers and fruits which are larger than those of T. malayana. Unlike T. macrocarpa, T. dubia does not differ in the leaves from T. malayana. The differences noted by Merrill (1915), like different angle of the nerves, disc glands with a different shape, and no mucro on the connective, could not be confirmed. Contrary to what Merrill reported, the connective does show a long appendix, usually much longer than in most specimens of T. malayana. T. dubia is kept separate because the differences in flower and fruit size are correlated with a disjunction in the distribution of the genus.
Trigonopleura macrocarpa Airy Shaw, Kew Bull. 36 (1981) 610; Welzen, Bulalacao & On, Blumea 40 (1995) 371, Fig. 2h; Map 1; Welzen & Esser in Noot. & Welzen, Fl. Males. ser. 1, 21 (2013) 131, fig. 2h; map 2. — Type: S (Rosli & Galau) 15747 (K, holo; iso in L), Borneo, Sarawak, Arboretum Semengoh Forest Reserve.
Tree, up to 30 m high, up to 1.5 m girth; flowering branches 2–2.5 mm thick, smooth, hirsute when very young. Leaves: stipules obovate, 2–2.5 by 0.6–0.7 mm; petiole 8–15 mm long, laterally flattened and deeply keeled on upper side with the walls touching, leaving a closed groove; blade ovate to elliptic, 5.7–14 by 2.5–5.5 cm, index 2.1–3, blackish brown when dry, margin revolute, upper and lower surface glabrous, nerves 6–8 per side. Bracts on brachyblasts c. 0.7 by 0.7 mm. Flowers c. 6.5 by 6 mm in diam., white, pistillate flowers not seen. Pedicels 2–5 mm long; upper part above abscission zone 1–2 mm long. Sepals ovate to obovate, 4.8–5.5 by 2–3 mm. Petals obovate, 5–5.3 by 1.6–2.4 mm in staminate flowers. Disc lobes 1.2–1.3 by 0.5–1.3 mm. Stamens in staminate flowers: androphore c. 5.3 mm long; filament c. 0.8 mm long; anther ± triangular, c. 1 by 0.9 mm. Pistil in pistillate flower not seen. Fruit c. 2.1 by 1.7 cm high; wall c. 4.3 mm thick. Seeds c. 7 by 5.7 mm; aril not observed; hilum c. 3.7 mm broad. Embryo not full-grown.
Distribution — Malesia: Sarawak, endemic in the Arboretum of Semengoh Forest Reserve near Kuching.
(square in Borneo; dots = T. dubia).
Habitat & Ecology — Found in lowland primary Dipterocarp forest on hill slopes. Alt.: c. 100 m. Flowering: September; fruiting: November.
Note — Typical for T. macrocarpa are the large flowers and fruits, and the shorter leaves with revolute margins which dry blackish brown. Some Bornean specimens of T. malayana resemble T. macrocarpa in the lack of indumentum and shape and colour of the dried leaves, however, their fruits and flowers are always smaller than those of T. macrocarpa. Some examples of glabrous T. malayana are: S 41134, 46802; SAN 17572, 41933, 44679.
Trigonopleura malayana Hook.f., Fl. Brit. India 5 (1887) 399; Hook. Ic. Pl. 18 (1888) t. 1753; Pax & K.Hoffm. in Engl., Pflanzenr. IV. 147. III (1911) 95, fig. 1b–d, 30; Ridl., Fl. Mal. Penin. 3 (1924) 263; Stern, Amer. J. Bot. 54 (1967)665, 667, 671, fig. 10; Whitmore, Tree Fl. Malaya 2 (1973) 134; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 201; Kew Bull. 36 (1981) 350; Welzen, Bulalacao & On, Blumea 40 (1995) 372, Fig. 2a, d–g, Map 2; Welzen & Esser in Noot. & Welzen, Fl. Males. ser. 1, 21 (2013) 132, fig. 2a, d–g; Map 3. — Lectotype (designated by Welzen et al., 1995): Maingay KD 1452 (K, holo), Malaya. (The other two syntypes, Scortechini specimens, were sterile).
Trigonopleura borneensis Merr., Philipp. J. Sc. Bot. 11 (1916) 76. — Type: Hose 676 (PNH, holo?, †; iso in BM, L; photo of BM sheet in A), Borneo, Sarawak, Miri River.
Peniculifera penangensis Ridl. (under Sterculiaceae), J. Roy. As. Soc. Str. Br. 82 (1920) 173; Fl. Mal. Penin. 1 (1922) 290. — Type: Curtis 3745 (K, holo), Malaysia, Penang, Government Hill.
Tree, up to 27 m high; d.b.h. up to 41 cm; buttresses up to 1.5 m long, 80 cm high, 12.5 cm thick; flowering branches 2.5–8 mm thick, ribbed to smooth, hirsute when young. Indumentum: white hairs. Bark with watery, yellow exudate; outer (red)brown to chocolate brown to dark grey, smooth to rough and lenticellate, c. 2 mm thick; inner reddish brown to (pale) brown, granular, soft, c. 1 cm thick. Sapwood white to light brown; heart wood dark brown; cambium yellow. Leaves: stipules obovate, 2.5–9 by 0.8–3 mm; petiole 6–12 mm long, reniform in transverse section to laterally flattened and deeply keeled on upper side with the walls touching, leaving a closed groove; blade (ovate to) elliptic to obovate, 4.8–19.5 by 2–8.2 cm, index 2.1–3(–3.8), red when young, darker green above when mature, margin flat (to revolute), upper surface glabrous except for the basal part of the midrib; lower surface subglabrous to hirsute, nerves 8–11 per side. Bracts on brachyblasts c. 0.7 by 0.7 mm. Flowers 5–6 by 4–7 mm in diam., fragrant. Pedicels 6–8 mm long; upper part above abscission zone 1.3–2.4 mm long. Sepals ovate to elliptic (to obovate), 2.3–4.3 by 1.3–3.5 mm, light green. Petals obovate, 3–3.8 by 1.1–1.3 mm in staminate flowers, 3.8–5.8 by 1.2–3 mm in pistillate flowers, white. Disc lobes 0.7–1.4 by 0.3–1.2 mm. Stamens in staminate flowers: androphore 4–5.2 mm long; filament 0.5–0.8 mm long, white; anther ± triangular, 0.7–1 by 0.4–0.8 mm, yellow. Pistil in pistillate flower: ovary ± globose, 2.3–2.6 by 1.3–2.3 mm; style 0.3–0.6 mm long; stigmas c. 2.5 mm long, lobes c. 1.8 mm long, glass-like to white. Fruit 0.9–1.3 by 1–1.3 cm high, red to purple; wall 1.5–2.3 mm thick. Seeds 4.5–5.7 by 4.5–5.2 mm; aril adaxially at most basally touching, pink; hilum 1.6–3.5 mm broad. Embryo 4.2–4.8 by 4–4.8 mm; plumule and radicle c. 1 mm long.
Distribution — Malesia: Peninsular Malaysia, Sumatra, Borneo (Indonesian Kalimantan, Sabah, Sarawak), and one specimen is known from Sulawesi (bb 29657).
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(dots = hirsute, broad-petioled leaves; squares = glabrous, narrow-petioled leaves) |
Habitat & Ecology — Found in primary Dipterocarp forest, secondary forest, riverine forest, submontane forest, along ridges and rivers, sometimes slightly swampy. Soil: limestone, sandy loam, granitic sand, sandstone, yellow sandy clay. Occurrence: very rare and scattered. Alt.: sea level up to 450(–1200) m. Flowering: March to October; fruiting: (March to) May to December.
Wood anatomy — See Stern, Amer. J. Bot. 54 (1967) 665, 667, 671, fig. 10.
Uses — The leaves can be eaten fresh or dried above a fire as a substitute of gambir when chewing sireh. The wood is used as fire wood.
Vernacular names — Peninsular Malaysia: Medang keladi. Sumatra: Gambir oetan; kaju salak; tjelangau. Borneo: Kalimantan: Gomi balua; Sabah: Gambir (Kadazan); gambir (Kadazan, Dusun-kinabatangan); gambir hutan (Malay); kadnoi/kadaloy/kadoroi/kodoloi/kodoroi (Dusun-kinabatangan); Sarawak: Akil (Malay); enkunit, kelali (Kayan); kayu sedi, kayu masam, sedi, selait, sidek kayu (Iban); kratuok (Dayak).
Note — This species is widespread on the Sunda Shelf (Map 2) and it is somewhat variable. In Peninsular Malaysia two forms can be seen, in the northern half the plants have narrow, grooved petioles and are almost glabrous, in the southern half the petioles are broad, more flat and the plants are very hairy. Examples of glabrous, narrow-petioled specimens: Curtis 1523, 3670, 3743; KEP 94455, 104857; KEP FRI 4488, 5745, 8324, 13303, 16136; King's collector 3610, 3650, 7587, 10178; Scortechini 738, 2056. Examples of pilose, broad-petioled specimens: CF 1977; KEP 105025; KEP FRI 7901, 7905, 7985, 16937; Maingay 1452; Maxwell 82-102; Sinclair 10588. No taxonomic distinction has been made, because the southern form is also found on Sumatra and Borneo, where subglabrous specimens are found with often also narrower petioles.
On Borneo the specimens can vary between (sub)glabrous (see note under G. macrocarpa), and then they are often found at higher altitudes, to hairy in most specimens to extremely hairy. The glabrous and very hairy forms are not geographically restricted. Examples of glabrous specimens are mentioned in the note under G. macrocarpa, examples of very hairy specimens are: Endert 1960; Guigonis 306; W. de Jong 445; Paymans 78.
