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Malesian Euphorbiaceae Descriptions |
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Epiprinus Griff., Notul. Pl. Asiat. 4 (1854) 487; Müll.Arg. in DC., Prodr. 15, 2 (1866) 1024; Benth. in Benth. & Hook.f., Gen. Pl. 3 (1880) 325; Hook.f., Fl. Br. India 5 (1887) 463; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.x (1919) 109; Ridl., Fl. Malay Penins. 3 (1924) 279; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1926) 474; Pax & K.Hoffm. in Engl. & Harms, Nat. Pflanzenfam. ed. 2, 19C (1931) 148; Corner, Ways. Trees Malaya (1940) 251; Croizat, J. Arnold Arbor. 23 (1942) 52; Airy Shaw, Kew Bull. 26 (1972) 259; Whitmore, Tree Fl. Malaya 2 (1973) 95; Airy Shaw, Kew Bull., Addit. Ser. 4 (1975) 9, in key; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 78; Govaerts, Frodin & Radcl.-Sm., World Checkl. Bibliogr. Euphorb. 2 (2000) 625; Radcl.-Sm., Gen. Euphorbiacearum (2001) 176; Chayam. in Chayam. & Welzen, Fl. Thailand 8 (2005) 257; Thin, Taxon. Euphorb. Vietnam (2007) 151; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 135. — Epiprinus Griff. subg. Euepiprinus Croizat, J. Arnold Arbor. 23 (1942) 53, nom. inval. — Epiprinus Griff. subg. Epiprinus: Thin, Taxon. Euphorb. Vietnam (2007) 151. — Type: Epiprinus malayanus Griff.
Genus description based on Epiprinus s.str. (without Symphyllia): Shrubs to trees, monoecious. Indumentum present on most parts, short, stellately grouped hairs, seldom simple hairs. Stipules very early caducous. Leaves alternate, simple, usually at the end of the branches, petiole bipulvinate; blades symmetric, papery when dry, margin entire (to serrate with glands in the tips), both surfaces smooth, stellately hairy on the venation, especially underneath, venation pinnate. Inflorescences terminal (to axillary in the upper leaves), spiciform (to paniculate), with basally sterile bracts, then single pistillate flowers per node and apically dense groups of staminate flowers per node, latter part caducous in fruit, bracteate, bracteoles distinct with pistillate flowers, bracts usually with two basal glands, bracteoles without glands, both with inconspicuous glands along the margin. Flowers unisexual, petals and disc absent. Staminate flowers subsessile; sepals irregularly splitting into 3 or 4 segments, valvate; stamens 5—10, filaments in bud either straight, sturdy and short or long and slender and basally horizontally folded two times and apically folded vertically two times, anthers dorsifixed, 2-thecate, thecae triangular, opening latro-extrorse via lengthwise slits, connective narrow with apical gland; pistillode shortly column-like, 3-partite, hairy. Pistillate flowers completely stellately hairy, pedicellate; pedicel 2.8–3.5 mm long, very sturdy, longitudinally grooved when dry, elongating in fruit; epicalyx usually present, 5 or 6(–11) small triangular elements, basally often with two glands, latter often persistent in fruit; sepals 5 or 6, alternating with epicalyx, reduplicate-valvate, accrescent in fruit; ovary 3-locular with 1 ovule per locule, style present, stigmas splitting several times, above with long, distinct papillae. Fruits ovate, 3-lobed schizocarps, splitting into 3 bivalved elements (completely septicidal, partly, from top, loculicidal) ; enveloped by large sepals; wall woody, not very thick. Seeds subglobose, naked.
Distribution — Four (Epiprinus s.str.) or six species (Symphyllia included), ranging from India to S. China, S.E. Asia and in one species in Malesia.
Notes — 1. According to Croizat (1942) the genus Symphyllia Baill. (synonyms: Adenochlaena Baill. sect. Symphyllia (Baill.) Hook.f.; Epiprinus Griff. subg. Symphyllia (Baill.) Croizat) is a synonym of Epiprinus, because E. balansae Gagnep. is intermediate. Various subsequent authors either accept (Webster, 1994; Radcliff-Smith, 2001) both genera, or unite them under Epiprinus (Croizat, 1942; Govaerts et al., 2000; Chayamarit, 2005; Thin, 2007). Symphyllia does not occur in Malesia and, therefore, this matter is not treated here. The absence of Symphyllia in the synonymy does not mean that both genera should remain separated. Morphologically, the two genera can easily be combined. Differences are the accrescent sepals in fruit (Epiprinus), the epicalyx (Epiprinus), the number of splits of the stigmas (higher in Epiprinus) and the number of stamens (4—6 – Symphyllia - versus 8—10 – Epiprinus). The epicalyx is not always present in all Epiprinus specimens, and the number of stamens is variable. The only real differences are the accrescense of the pistillate sepals and the degree of splitting of the stigmas. Unifying characters are the folding of the stamens in bud (not in all species), the dorsal attachment of the filaments, the presence of a small gland on top of the connective.
2. Webster (1994) and Radcliffe-Smith (2001) place Epiprinus in subfam. Acalyphoideae tribe Epiprineae subtribe Epiprininae (Symphyllia is similarly classified).
Epiprinus malayanus Griff., Notul. Pl. Asiat. 4 (1854) 487; Müll.Arg. in DC., Prodr. 15, 2 (1866) 1024; Hook.f., Fl. Br. India 5 (1887) 464; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.x (1919) 110; Ridl., Fl. Malay Penins. 3 (1924) 279; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1926) 474, in key; Corner, Ways. Trees Malaya (1940) 252, text-fig. 77; Airy Shaw, Kew Bull. 16 (1963) 356; Kew Bull. 26 (1972) 259; Whitmore, Tree Fl. Malaya 2 (1973) 95; Govaerts, Frodin & Radcl.-Sm., World Checkl. Bibliogr. Euphorb. 2 (2000) 625; Chayam. in Chayam. & Welzen, Fl. Thailand 8 (2005) 258, fig. 64, plate XIV. — Type: Griffith KD 4787 (holotype K, with flowers; isotypes K 2x in fruit, one Griffith s.n., also in fruit), (Malaysia,), [Malaysia], according to precursor: Malacca, Ching, Nhing Hull [labels without information].
Shrubs to trees, up to 20 m high, up to 20 cm diameter, crown often thin; twigs dark red, flowering branches 4–6 mm thick. Outer bark smooth to somewhat rough to lenticellate, c. 1 mm thick, brown to patchy light brown and grey to grey; inner bark c. 2 mm thick, yellowish to yellow-green to pale green (to brown); wood white to yellow-white (to brown). Stipules triangular to long elliptic, 3.5–11.8(–16) by 1.3–1.5 mm, outside stellately hairy, inside sericeous with simple hairs, basally 2 glands outside. Leaves red then yellow when young; petiole (not of the subsessile upper leaves) (0.3–)5–20.4 cm long, round except basally flattened above, longitudinally grooved when dry, stellately hairy, apically two or more glands, the largest on spreading stipellae; blade ovate to elliptic, 9–41 by 3.3–20 cm, length/width ratio 2–2.7, basally emarginate to rounded to widely cuneate, margin entire, revolute, apex cuspidate, upper surface dark green, drying greenish; lower surface pale green, drying brownish green, venation slightly raised above, strongly raised underneath, nerves 9–12 pairs, tertiary veins ± scalariform, quaternary and higher order veins reticulate. Inflorescences terminal, 3.5–24 cm long, reddish, staminate part very condense, separate nodes usually not well visible; lowest bracts often leaf-like, usually (sub)sessile, base emarginate; higher bracts triangular, stipule-like, 3–9 by 1.8–4 mm, completely stellately hairy; bracteoles like bracts, smaller. Flowers pink to red, slightly fragrant. Staminate flowers 6–7.5 mm diam.; sepals ovate to round, 3–4.2 by 2.3–3.3 mm, outside stellately hairy, inside glabrous; stamens 8–10, filaments long, slender, folded in bud, tapering towards the apex, 7–10 mm long, glabrous, white, anthers 1.5–2.8 by 1–1.3 mm, yellow, with stellate hairs, one theca generally larger than other; pistillode 0.8–2 by 0.3–0.5 mm. Pistillate flowers 6–21 mm in diameter, ; pedicel 2.8–3.5 mm long, very sturdy, grooved when dry; epicalyx elements usually present (sometimes absent on Sumatra), ovate to triangular, 3.6–4.8 by 1.2–1.8 mm, margin with inconspicuous glands; sepals 6, ovate-elliptic, 5–9 by 1.8–4 mm, midrib thickened; ovary ovate, 3-lobed, 2.5–3 by 2–2.5 mm, style 4–8 mm long, crimson-rose, stigma up to 10 mm long, first split at 2/3rd of style, apically splitting twice to several times more. Fruits 15–20 mm high by c. 16 (1 lobe developed), 19–30 mm wide, red to pink-red; pedicel up to 4.8 cm long, sepals ovate, 2.9–5 by 1.4–3.4 cm, dark red to purplish red; style and epicalyx elements often persistent. Seeds 11–12 mm in diameter, cream, often marbled.
Distribution — Southern part of the Thai Peninsula, Malay Peninsula, Sumatra; according to Govaerts et al. (2000) also in Burma.
Habitat & Ecology — Primary lowland rain forests, evergreen forests, secondary forests, usually on hillsides, also often along water; soil sand and shale. Altitude: 33–600 m. Flowering January to March, June, August, December; fruiting: May to September, December.
Vernacular names — Malay Peninsula: Balong hijau, Chendur, Chindra, Jarak hitam, Munot (Ridley, 1924); Beliboh; Kayu rengkow (Temuan); Kemesul.
Notes — 1. The variety balansae Pax & K.Hoffm. is raised to species level as E. balansae (Pax & K.Hoffm.) Gagnep.This species has shorter petioles, glands on petiole smaller and often single, serrate leaf margins with glandular teeth; staminate groups of flowers distinct from each others in bud; stamens 8, not folded.
2. The pistillate calyx of Sumatran specimens is more accrescent in fruit than those of the Malay Peninsula, also Sumatran specimens sometimes lack the pistillate epicalyx.
