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Malesian Euphorbiaceae Descriptions |
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Welzen, P.C. van. 2016. Bischofia and Hymenocardia (Phyllanthaceae) in Malesia. Blumea 61: 272-279.
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Hymenocardia Wall. ex Lindl., Intr. Nat. Syst. Bot. ed. 2 (1836) 441; Enl., Gen. Pl. (1837) 288 (nr. 1899); Tul., Ann. Sci. Nat., Bot. sér. 3, 15 (1851) 256; Baill., Bull. Soc. Bot. France 4 (1857) 994; Étude Euphorb. (1858) 599, pl. 27: fig. 24, 25; Müll.Arg. in A.DC., Prodr. 15, 2 (1866) 476; Kurz, Forest Fl. Burma 2 (1877) 394; Benth. in Benth. & Hook.f., Gen Pl. 3 (1880) 285; Hook.f., Fl. Brit. India 5 (1887) 376; Pax in Engl. & Prantl, Nat. Pflanzenfam. 3, 5 (1890) 30; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xv (1922) 72; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1927) 543; Pax & K.Hoffm. in Engl. & Harms, Nat. Pflanzenfam. ed. 2, 19c (1931) 51; Airy Shaw, Kew Bull. 18 (1964) 262; Kew Bull. 26 (1972a) 363; Whitmore, Tree Fl. Mal. 2 (1973) 103; Radcl.-Sm., Bot. J. Linn. Soc. 94 (1987) 52; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 53; Govaerts et al., World Checkl. & Bibliogr. Euphorbiaceae (2000) 1013; Radcl.-Sm., Gen. Euphorbiacearum (2001) 74; Welzen in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 341; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 82, fig. 15; Welzen, Blumea 61 (2016) 275. — Type: Hymenocardia punctata Wall. ex Lindl.
Samaropyxis Miq., Fl. Ned. Ind., Eerste Bijv. (1860) 464. — Type: Samaropyxis elliptica Miq. (= Hymenocardia punctata Wall. ex Lindl.).
Shrubs to trees, dioecious, deciduous, leaves appearing during flowering; branches hairy with scale-like hairs and simple hairs when young. Indumentum of simple and scale-like hairs (recorded as glandular). Stipules triangular, thick, early caducous. Leaves distichous (to opposite) on branches, simple; petiole not pulvinate, reniform in transverse section; blades elliptic, margin entire, glabrous above to hairy on midrib with simple hairs, hairy beneath, venation densely reticulate, few nerves, latter looped and closed near margin. Inflorescences dense spikes to panicles, axillary and catkin-like when staminate, terminal and few-flowered racemes when pistillate; flowers bracteate. Flowers actinomorphic; petals and disc absent. Staminate flowers: pedicel very short; calyx mainly 5-lobed, cupular, lobes triangular, imbricate to almost valvate; stamens mainly 5, episepalous, basally united or free, anthers very large, 2-thecate, dorsifixed, horizontal when dehiscing extrorse via lengthwise slits, connective with subapical, dorsal gland; pistillode on top of androphore, a short cylinder, apically slightly 2-lobed. Pistillate flowers shortly pedicelled, sepals (4)5(8), free, long-triangular, valvate, soon caducous leaving cup-shaped scars; ovary 2-locular, flattened; ovules 2 per locule; style absent or minute, stigmas 2, unlobed, long papillate. Fruits flat, 2-lobed, usually heart-shaped, samara-like capsules (rhegmas), winged or not. Seeds usually 1 per locule developed, naked.
Distribution ― A genus of six species (Govaerts et al. 2000), of which five in continental Africa and one in Southeast Asia main land and W Malesia.
Hymenocardia punctata Wall. [Numer. list (1831) nr. 3549] ex Lindl., Intr. Nat. Syst. Bot. ed. 2 (1836) 441; Hook.f., Fl. Brit. India 5 (1877) 377; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xv (1922) 72; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1927) 542; Airy Shaw, Kew Bull. 26 (1972a) 363; Whitmore, Tree Fl. Mal. 2 (1973) 103; Govaerts et al., Worl Checkl. & Bibliogr. Euphorbiaceae (2000) 1013; Welzen in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 341, fig. 10; Plate XIX: 1; Welzen, Blumea 61 (2016) 277, fig. 2, map 2. — Lectotype (designated by Welzen 2016): Wallich no. 3549 (K, K001119695; iso G, G-DC, 2 sheets, K, K001119696), Burma, Moolmyne, river Akan? at Salum.
Hymenocardia wallichii Tul., Ann. Sci. Nat., Bot. Sér. 3, 15 (1851) 256; Müll.Arg. in A.DC., Prodr. 15, 2 (1866) 476; Kurz, Forest Fl. Burma 2 (1877) 394; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xv (1922) 78, fig. 8e; Gagnep. in Lecomte, Fl. Indo-Chine 5 (1927) 544. — Type: Wallich no. 3549 (G-DC holo; iso G, , 2 sheets, K, 2 sheets), Burma, Moolmyne, river Akan? at Salum. N.B. same duplicates as for H. punctata.
Hymenocardia wallichii Tul. var. dasycarpa Gagnep. in Lecomte, Fl. Indo-Chine 5 (1927) 546.— Type: Thorel s.n. (not seen), Cambodia, Compong-luong.
Samaropyxis elliptica Miq., Fl. Ned. Ind., Eerste Bijv. (1860) 465. — Type: Teijsmann HB 4248 (holo U), Sumatra, prov. Lampong, prope Marassa.
Hymenocardia laotica Gagnep., Bull. Soc. Bot. France 23 (1923) 436; in Lecomte, Fl. Indo-Chine 5 (1927) 546, fig. 68: 1. ― Type: Thorel 1283 (holo P; iso A), Laos, Stung-streng (A sheet: Me-Kong, Stong Treng).
Shrubs to trees up to 7 m high, dbh up to 9 cm; flowering branches 2-4.5 mm thick. Bark thin, smooth to finely roughened to roughly cracked and flaking, grey to grey-brown. Indumentum present on most parts, scale-like hairs yellow, stipules and floral parts inside glabrous. Stipules 1–3 by 0.2–1 mm. Leaves: petiole 0.5–1.2 cm, hairy, especially above; blade elliptic, 2.2–9 by 1.4–5.2 cm, length/width ratio 1.7–2.1, base emarginate to rounded (to cuneate), apex acute to acuminate, upper surface shiny, green, lower surface densely scaly, at most hairy on nerves and midrib, with (indistinct) hair tuft domatia, dull light green; venation sunken to slightly raised above, raised underneath, nerves 6-8 per side. Staminate inflorescences axillary catkins, up to 2.5 cm long, axes dull light yellow-green; bracts pedicelled, pedicel up to 0.5 mm long, blade subpeltate, triangular, c. 0.5 by 0.4 mm. Staminate flowers c. 1.5 mm in diameter, red to purple; pedicel up to 0.5 mm long, calyx c. 1.5 mm long, lobes 0.4-0.7 by 0.4-0.7 mm, pale light greenish; stamens 4 or 5, united with pistillode, androphore 0.4-0.5 mm long, filaments pale pinkish-white, c. 1 mm long, anthers c. 1 by 0.7 mm, dark red; pistillode c. 1.2 mm long. Pistillate inflorescences racemes, up to 2 cm long, axes grey-tan; bracts ovate, c. 1 by 1 mm, dull light greenish, early caducous. Pistillate flowers c. 1 mm in diameter, brown; pedicel up to 2 mm long; sepals 5, triangular, 0.7-1.2 by 0.3-0.5 mm; ovary flat, ± diamond-shaped, 0.3-1 by 0.3-1 mm, green to glossy dark maroon; stigmas 1-15 mm long (elongating with age), maroon. Fruits not winged, heart-shaped with horizontal lobes, 1.6-2.1 by 1.1-1.5 cm, changing from maroon to brownish green to yellowish; columella very slender, c. 13.5 mm long, apically hardly broadened. Seed unripe?, flat, obovate, c. 6 by 3.5 mm.
Distribution — Myanmar, Thailand, Laos, Cambodia, Malay Peninsula, Sumatra.
Habitat & Ecology — In primary to secondary dry dipterocarp forest to mixed deciduous forest, very often along water, like along beaches, rivers, lakes, but also very often in open scrubs, roadsides or at the border between cultivated and natural vegetations. The plant is considered to be a pioneer. Soils generally wet; bedrock sand, sandstone, rhyolite. Altitude: sea level up to 235 m. Flowering: October, December till May; fruiting: February till October.
Vernacular names — Sumatra: Mersepang, Sepang, Sesepang, Serpang.
Uses — Cambodia: Fruits sour, used in cooking. Bark and roots used medicinally.
Hymenocardia plicata Kurz, Forest Fl. Burma 2 (1877) 395. ― Lectotype (designated by Bollendorff et al. 2000: 331) Kurz 1554 (K), Burma, Tomkgeghat, 7 Pagodas = Mallotus plicatus (Müll.Arg.) Airy Shaw (see Bollendorff SM, van Welzen PC, Slik JWF. 2000. A taxonomic revision of Mallotus Section Polyadenii (Euphorbiaceae). Blumea 45: 319-340).
Note ― Probably described in Hymenocardia because of the heart-shaped, winged fruits and the presence of glandular, scale-like hairs. However, the indument (stellate hairs), and flowers are completely different, the fruits are 3-locular, instead of 2-locular, and the locules are thicker, not flat.
