Flora of Thailand

Euphorbiaceae

 

49. Hymenocardia

 

P.C. van Welzen

 

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Genus description

Species description

 

Hymenocardia

 

Wall. ex Lindl., Intr. Nat. Syst. Bot. ed. 2: 441. 1836; Hook.f., Fl. Brit. India 5: 376. 1887; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xv: 72, Fig. 8, 9. 1922; Gagnep. in Lecomte, Fl. Indo-Chine 5: 543, Fig. 68: 1. 1927; Airy Shaw, Kew Bull. 26: 363. 1972; Whitmore, Tree Fl. Mal. 2: 103. 1973; G.L.Webster, Ann. Missouri Bot. Gard. 81: 53; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 341. 2007; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11: 82, Fig. 15. 2014; Welzen, Blumea 61 (2016) 275.— Samaropyxis Miq., Fl. Ned. Ind., Eerste Bijv.: 464. 1860.

 

Trees, dioecious, deciduous, leaves appearing during flowering. Indumentum of simple and scale hairs (also recorded as glandular). Stipules triangular, early caducous. Leaves distichous on branches, simple; petiole not pulvinate, reniform in transverse section; blades elliptic, margin entire, glabrous above, hairy beneath, venation densely reticulate, few nerves, latter looped and closed near margin. Inflorescences axillary, dense spikes to panicles, catkin-like when staminate, few-flowered racemes when pistillate; flowers bracteate. Flowers actinomorphic; petals and disc absent. Staminate flowers: pedicel very short; calyx mainly 5-lobed, lobes triangular, valvate; stamens mainly 5, episepalous, united or free, anthers very large, 2-locular, dorsifixed, horizontal and extrorse when dehiscing, with subapical, dorsal gland; pistillode very shortly 2-lobed. Pistillate flowers shortly pedicelled, sepals (4)5(8), free, long-triangular, valvate; ovary 2-locular, flattened; ovules 2 per locule; style absent, stigmas 2, unlobed, long papillate. Fruits flat, 2-lobed, usually heart-shaped samaras, winged or not. Seeds usually 1 per locule developed, naked.

    Nine species, most of them in Continental Africa, one in S.E. Asia, also found in Thailand. Classification: Subfam. Phyllanthoideae, tribe Hymenocardieae.

 

1. Hymenocardia punctata Wall. ex Lindl., Intr. Nat. Syst. Bot. ed. 2: 441. 1836; Hook.f., Fl. Brit. India 5: 377. 1887; Airy Shaw, Kew Bull. 18: 262. 1965; Kew Bull. 26: 363. 1972; Whitmore, Tree Fl. Mal. 2: 103. 1973; Welzen in Welzen & Chayam., Fl. Thailand 8, 2: 341, Fig. 10; Plate XIX: 1.— Hymenocardia wallichii Tul., Ann. Sci. Nat. Sér. 3, 15: 256. 1851; Welzen, Blumea 61 (2016) 277, fig. 2, map 2.— Samaropyxis elliptica Miq., Fl. Ind. Bat. Suppl.: 465. 1860.— Hymenocardia wallichii Tul. var. dasycarpa Gagnep. in Lecomte, Fl. Gén. I.-C. 5: 546. 1927.— Hymenocardia laotica Gagnep. in Lecomte, Fl. Indo-Chine 5: 546, Fig. 68: 1. 1927

 

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Shrubs to trees up to 4(–7) m high. Bark grey-brown. Indumentum present on most parts, floral parts inside glabrous. Stipules 1–3 by 0.2–1 mm. Leaves: petiole 0.5–1.2 cm; blade elliptic, 2.4–8.5 by 1.4–4 cm, length/width ratio 1.7–2.1, base emarginate to rounded (to cuneate), apex acute to acuminate, upper surface glabrous, shiny, lower surface densely scaly, at most hairy on nerves and midrib, often with indistinct hair tuft domatia; nerves 6--8 per side, sunken above, veins raised. Staminate inflorescences catkins, up to 2.5 cm long; bracts pedicelled, pedicel up to 0.5 mm long, blade triangular, subperlated, 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 c. 0.7 by 0.7 mm; stamens 4 or 5, united with pistillode, anthers c. 1 by 0.7 mm. Pistillate inflorescences racemes, up to 1.5 cm long; bracts early caducous. Pistillate flowers c. 1 mm in diameter, brown; pedicel up to 0.5 mm; sepals 5, triangular, c. 1.2 by 0.4-0.5 mm; ovary green; stigmas up to 8.5 mm long, maroon. Fruit not winged, heart-shaped, c. 1.6 by 1.2 cm, brownish green to yellowish.

    T h a i l a n d.— NORTHERN: Sukhothai (Yang-N), Nakhon Sawan (Nakhon Sawan); EASTERN: Nakhon Ratchasima (Kao Samung), Si Sa Ket (Ban Datat, Nong Pha Naeng, Uthum Phon Phisai); SOUTH-EASTERN: Prachin Buri (Ban Muang Kao), Chanthaburi (Chanthaburi); PENINSULAR: Phangnga (Phanom).

    D i s t r i b u t i o n.— Myanmar (type), Thailand, Laos, Cambodia, Vietnam?, Malay Peninsula, Sumatra.

 

Hymepunc-map.gif (30803 bytes)

 

    E c o l o g y.— In primary to secondary dry dipterocarp forest to mixed deciduous forest, open scrubs, thickets, along rivers, beach flora (considered to be a pioneer); on dry to wet soils. Altitude: sea level up to 235 m.

    V e r n a c u l a r.— Kang pla khao (ก้างลา) (Sukhothai); mak faep (หมัก) (Phitsanulok); hu ling (ูล) (Nakhon Ratchasima); hu dang (ูด้าง) (Surin); faep nam (น้) (Prachuap Khiri Khan); khwaep (), faep () (Chon Buri); faep hua ling () (Peninsular).

    U s e s.— Cambodia: Fruits sour, used in cooking. Bark and roots used medicinally.