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Malesian Euphorbiaceae Descriptions |
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Welzen, P.C. van, Pruesapan, K, Telford, I.R.H., Esser, H.-J. & Bruhl, J.J. 2014. Phylogenetic reconstruction promps taxonomic changes in Sauropus, Synostemon and Breynia (Phyllanthaceae tribe Phyllanteae). Blumea 59: 77–94.
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Synostemon F.Muell., Fragm. Phyt. Austral. 1 (1858) 32; Backer & Bakh.f., Fl. Java 1 (1963) 470; Airy Shaw Kew Bull. 26 (1972) 343; Whitmore, Tree Fl. Malaya 2 (1973) 130; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 199; L.C.Wheeler, Taxon 24 (1975) 537; Airy Shaw, Kew Bull. Add. Ser. 8 (1980a) 205; Welzen et al., Blumea 59 (2014) 89. — Lectotype (designated by L.C.Wheeler, 1975): Synostemon ramosissimus F.Muell.
Agyneia auct. non L.: Vent., Decr. Pl. Nouv. (1800) 23, t. 23; A.Juss., Euphorb. Gen. (1824) 24; Hook.f., Fl. Br. India 5 (1887) 285. — Type: Agyneia impubes Vent., non L. [= Synostemon bacciformis (L.) G.L.Webster].
Diplomorpha Griff., Not. Pl. Asiat. 4 (1854) 479. — Type: Diplomorpha herbacea Griff. [= Synostemon bacciformis (L.) G.L.Webster].
Heterocalymnantha Domin, Biblioth. Bot. 89 (1927) 313. — Type species: Heterocalymnantha minutifolia Domin [= Synostemon rigens F.Muell.].
Annual herbs to shrubs, monoecious or dioecious; branches terete or ribbed. Indumentum of simple hairs or absent. Stipules mainly triangular, late caducous. Stem leaves (on orthotropic growth) alternate, mainly laminate on young shouts (to throughout), larger but similar to branchlet leaves, usually scale-like distally (phyllanthoid branching) (to scale-like throughout). Branchlet leaves (on plagiotrophic growth) usually distichous, simple, petiolate; blade symmetric, somtimes scale-like, basally attached, margin entire, surfaces without glands, generally drying greenish; venation usually indistinct, pinnate, veins reticulate. Inflorescences axillary fascicles of single to several bracteate flowers (when older short racemes), pistillate at the top of branches or racemes, staminate at lower nodes, the latter often in short bracteate racemes with a few flowers apically. Flowers actinomorphic, pedicellate, generally hanging down; sepals 6, in two whorls, free to almost completely connate, sexes usually dissimilar, pistillate flowers larger; petals, disc, and pistillode absent. Staminate flowers: sepals free, usually spreading, or connate and cup-like with 6 or 12 lobes, sometimes scales at base of lobes; stamens 3, united into central vertical androphore and apically 3-branched with anthers underneath or not splitting and anthers longitudinally along it, anthers 2-thecate, extrorse. Pistillate flowers: calyx persistent; ovary 3-locular, ovules 2 per locule; style mostly absent, stigmas 3, entire or variously bifid, sometimes completely. Fruits rhegmas, ovoid or ellipsoid, often longer than broad, 6-seeded, cartilaginous; columella persistent. Seeds crescent moon-like, ornamented, ecarunculate.
Distribution — A genus of 40 species, mainly present in Australia, one also in New Guinea, and one widespread, ranging from the Mascarenes to S and SE Asia, throughout Malesia to Australia.
Note — The genus was recently resurrected (van Welzen et al. 2014) based on phylogenetic evidence. The genus forms a monophyletic group within a larger Phyllanthoid clade.
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1a. |
Androphore apically splitting into three with anthers underneath branches. Branchlets with mainly 4 ribs. Pistillate flowers 3–5.5 mm in diameter — littoral, near sea |
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1b. |
Androphore apically not splitting, anthers longtudinally along androphore. Branchlets with 2 ribs. Pistillate flowers c. 4.5 mm in diameter — not along sea |
Synostemon bacciformis (L.) G.L.Webster, Taxon 9 (1960) 26, in adnot.; Backer & Bakh.f., Fl. Java 1 (1963) 471; Airy Shaw, Kew Bull. 26 (1972) 343; Whitmore, Tree Fl. Malaya 2 (1973) 133; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 199
; Welzen et al., Blumea 59 (2014) 89. — Phyllanthus bacciformis L., Mant. Pl. (1767) 294. — Agyneia bacciformis (L.) A.Juss., Euphorb. Gen. (1824) 24, t. 6.; Blume, Bijdr. (1825) 595; Müll.Arg. in DC., Prodr. 15, 2 (1866) 238; Hook.f., Fl. Br. India 5 (1887) 285; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.xv (1922) 213; Beille in Lecomte, Fl. Indo-Chine 5 (1927) 642, Fig. 76; Merr. & Chun, Sunyatsenia 5 (1940) 91; Steenis, Bull. Jard. Bot. Buitenzorg ser. 3, 17 (1948) 410. — Agyneia phyllanthoides Spreng., Syst. Veg. 3 (1826) 19, nom. illig., nom. superfl. — Diplomorpha bacciformis (L.) Kuntze, Revis. Gen. Pl. (1891) 603. — Sauropus bacciformis (L.) Airy Shaw, Kew Bull. Add. Ser. 8 (1980a) 221; Kew Bull. 35 (1980b) 685; Kew Bull. 36 (1981) 343; Kew Bull. 37 (1982) 34; Chakrab. & M.G.Gangop., J. Econ. Tax. Bot. 20 (1996) 523, Fig. 1: a–f; Philcox, Rev. Handb. Fl. Ceylon 13 (1999) 100; Smitinand, Thai Pl. Names, rev. ed. (2001) 467; Welzen, Blumea 48 (2003) 345, map 5; in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 529. — Breynia bacciformis (L.) Chakrab. & N.P.Balakr., Bangladesh J. Pl. Taxon. 19 (2012) 120. — Lectotype (designated by Scott in Bosser et al., Flor. Mascar., fam. 153–160. 1982: 37: Koenig s.n. (n.v.), S. India, Tranquebaria.Phyllanthus racemosus L.f., Suppl. Pl. (1781) 415. — Emblica racemosa (L.f.) Spreng., Syst. Veg. 3 (1826) 20. 1826. — Type: Koenig s.n. (n.v.), Sri Lanka (Ceylon).
Agyneia impubes Vent., Descr. Pl. Jard. Nouv. (1800) 23, tab. 23. — Type: Bojer s.n. (K), Mauritius.
Diplomorpha herbacea Griff., Not. Pl. Asiat. 4 (1854) 479. — Type: Not indicated (n.v.), India.
Phyllanthus goniocladus Merr. & Chun, Sunyatsenia 2 (1935) 260, t. 51. — Type: F.C. How 70913 (holo NY; iso A), China, Hainan, Yaichow (Ngai Yuen).
Sauropus gramineus Airy Shaw, Kew Bull. 35 (1980b) 389. — Type: Kerr 8472 (holo K; iso BM), Thailand (Siam), Northeastern (Udawn Circle), Nakhon Phanom Prov. (Nakawn Panom), Ta Uten. See note.
Herbs to subshrubs up to 50 cm high, pale green, branches with mainly 4 ribs, flowering branches c. 1.5 mm thick. Indumentum absent. Stipules triangular to falcate, 1.7–3 by 0.5–1.5 mm, papery, rather persistent, often with very small asperities along margin and midrib beneath. Leaves: petiole less than 1 mm long, flattened above; blade elliptic, 6.5–25 by 1.5–7(–13) mm, length/width ratio 1.5–7.8, pergamentaceous (fleshy when fresh), base rounded, margin flat, without asperities, apex rounded to acute, lower surface somewhat papillate and glaucous; nerves very indistinct, only midrib distinct beneath. Inflorescences axillary fascicles; flowers green to light purple, several together (staminate) or single (pistillate), pistillate flowers at end of branches. Staminate flowers 1.2–1.5 mm in diameter; pedicel c. 0.6 mm long; calyx lobes deeply divided, ovate, 0.4–0.6 by 0.3–0.4 mm, scales subapically on inside, apex entire, rounded; stamens: androphore c. 0.2 mm high; stamens c. 0.2 by 0.2–0.3 mm Pistillate flowers 3–5.5 mm in diameter; pedicel 3–4 mm long; sepals free, ovate, 2–2.8 by 1–1.4 mm, apex acute, reflexed in fruit; ovary obtruncate, 1–1.3 by 0.9–1 mm, apically with fleshy extensions basally to styles; styles c. 0.5 mm long, erect, upper half split, hardly coiled. Fruits ovoid, 5–5.2 by 5.5–6.5 mm, green, with apically lobed rim around stigmas; column 3.2–3.3 mm long, with ellipsoid thickening above middle till apex. Seeds triangular in section, 4.5–4.9 by 1.2–1.8 by 1.2–1.5 mm, surface strobiculate.
Distribution — Mauritius, Maldives, India, Sri Lanka, S. China, S.E. Asia main land, W. Malesia: Malay Peninsula, Java, Borneo, Philippines, and Lesser Sunda Islands (Timor).
Habitat & Ecology — Especially along or near beaches, usually in sun, also recorded to be common in wet, grassy roadsides, edges of rice fields, along path through mangrove, tidal flats and in open waste grounds; soil: usually silty sand, clay, limestone. Altitude: sea level up to 200(–1800) m. Flowering en fruiting whole year through.
Vernacular names — Thailand:
Ma pharo nok khao, Soi nok khao (official Thai name), Thong laeng.Note — Airy Shaw (1980b) states that, even though the habit and leaves of S
auropus gramineus resemble those of S. bacciformis, the staminate flowers are like those of Breynia quadrangularis (Willd.) Chakrab. & N.P.Balakr. (formerly Sauropus quadrangularis (Willd.) Müll.Arg.). However, a study of the type showed a perfect match of the staminate flowers with those of S. bacciformis. Therefore, the name Sauropus gramineus is synonymized with S. bacciformis.
Synostemon sphenophyllus Airy Shaw, Kew Bull. 33 (1978) 37; Kew Bull. Add. Ser. 8 (1980a) 205. — Sauropus sphenophyllus (Airy Shaw) Airy Shaw, Kew Bull. Add. Ser. 8 (1980a) 221; Kew Bull. 35 (1980b) 686; Welzen, Blumea 48 (2003) 374, map 19. — Type: NGF (Henty & Katik) 38763 (holo BRI; iso L), Papua New Guinea, Western Prov., Morehead Subprov., Sibidiri, Mai Kussa River, 142.15 E, 8.59 S.
Shrub, up to 1.5 m tall; branches with 2 small ribs, with asperities when young, flowering branches 0.2–0.3 mm thick. Indumentum absent. Stipules triangular, 0.8–1.2 by 0.5–0.6 mm, pergamentaceous, whitish/yellowish when dry except for the base, rather persistent. Leaves: petiole 0.5–1 mm long, flattened above; blade obovate, 1–2.8(–4) by 0.7–1.1 cm, length/width ratio 1.4–3.6, pergamentaceous, base cuneate, margin recurved, apex emarginate to rounded, mucronulate, upper surface green when dry, lower surface lighter green, papillate; venation raised and distinct on both sides, nerves 6–9 per side, veins and veinlets reticulate. Inflorescences axillary fascicles; flowers usually solitary, yellowish. Staminate flowers c. 3 mm in diameter; pedicel c. 4 mm long; calyx c. 1.2 mm deep, lobes almost free, obovate, 1–1.1 by 0.7–1.2 mm, apex rounded, scales lacking; stamens of Breynia-type: androphore c. 1.3 mm long, basal part c. 0.5 mm long, apically not split into horizontal branches but erect, anthers c. 0.8 by 0.3 mm, along androphore, elongation of connective c. 0.2 mm long. Pistillate flowers c. 4.5 mm in diameter; pedicel c. 6.5 mm long; calyx lobes obovate, 2.2–2.5 by 0.8–1.1 mm, apex rounded; ovary obtrapezoid, c. 1 by 1.2 mm, apically forming three cushions around the subapical stigmas; stigmas c. 1 mm long, erect, free, apically not split but slightly bent. Fruits not seen.
Distribution — Papua New Guinea (Western Prov.) and northeastern Australia (Queensland, Cape York).
Habitat & Ecology — Woodland on low hill. Altitude: 150 m. Flowering and fruiting: July.
Notes — 1. According to Airy Shaw (1978, 1980a) strongly resembling S. albiflorus (F.Muell. ex Müll.Arg.) Airy Shaw, of eastern Queensland. The latter species has less cuneate, smaller leaves which are seemingly more glaucous; the branches lack the asperities.
