Malesian Euphorbiaceae Descriptions

71. MELANOLEPIS (Euphorbiaceae)

 

Peter C. van Welzen, Kartika Ning Tyas, Eviyarni & F.J.M. Gaerlan

 

Welzen, P.C.  van, Kartika Ning Tyas, Eviyarni & F.J.M. Gaerlan. 1999. The Malesian species of Melanolepis (Euphorbiaceae). Blumea 44: 437446.

 

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Genus description

Species description

 

Melanolepis Rchb.f. & Zoll.

 

    Melanolepis Rchb.f. & Zoll., Acta Soc. Regiae Sci. Indo-Neerl. 1 (1856) 22; Linnaea 28 (1856) 324; Merr., Interpr. Herb. Amboin. (1917) 318; Corner, Ways. Trees Malaya (1940) 274; Backer & Bakh.f., Fl. Java 1 (1964) 481; Airy Shaw, Kew Bull. 26 (1972) 309; Whitmore, Tree Fl. Malaya 2 (1973) 118; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 175; Kew Bull. Add. Ser. 8 (1980) 174; Kew Bull. 36 (1981) 332; Kew Bull. 37 (1982) 30; Alph. Enum. Euphor. Philipp. Isl. (1983) 38; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 73; Welzen et al., Blumea 44 (1999) 438; Radcl.-Sm., Gen. Euphorbiacearum (2001) 150; Welzen in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 444; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 142. — Type: Melanolepis multiglandulosa (Reinw. ex Blume) Rchb.f. & Zoll.

 

Shrubs to trees, presumably monoecious, but usually only one sex per plant; flowering twigs smooth, lenticellate, glabrous except when young, with a broad soft pith. Indumentum mainly consisting of stellate hairs, only a few simple hairs. Stipules deltoid, densely hairy except for glandular apex and basal glands on the inside, caducous. Leaves spirally arranged, simple; petiole relatively long, basally usually constricted, filled with soft pith; blade ovate, sometimes 3-lobed, papery, usually symmetric, base cordate to cuneate, with a group of protruding glands on the upper surface, margin inconspicuously to very coarsely dentate, with glands in teeth and smaller ones along the margin, apex acute to acuminate, very apex acute, usually green when dry with whitish venation, upper surface glabrous except for a few basal hairs, lower surface sparsely to very densely hairy, often with 2 basal black glandular areas (esp. in New Guinea) and additional smaller glandular areas along the veins; venation palmate with 5 (7) major nerves, secondary nerves ending in marginal teeth, not interconnected, veins scalariform, quaternary veins more reticulate. Inflorescences terminal panicles, very laxly (1-3) branched (therefore raceme-like) with either staminate or pistillate flowers, seldom both sexes on the same inflorescence, more often both sexes present on different inflorescences, erect; staminate flowers up to 5 per cymule, pistillate flowers single or 2 (seldom with a few staminate ones) per cymule. Bracts and bracteoles broadly ovate to deltoid, outside hairy, inside glabrous. Flowers actinomorphic, sepals (4) 5, valvate, petals absent. Staminate flowers pedicellate; sepals ovate, outside densely puberulous with simple and stellate hairs, inside glabrous; stamens 200–250, free, filaments thread-like, anthers basidorsifixed just below the apidorsal gland on the connective, 2-locular, opening introrsely with lengthwise slits; disk and pistillode absent; receptacle convex. Pistillate flowers: pedicel elongating in fruit; sepals basally united into calyx, lobes triangular to ovate, outside densely tomentose, inside only apically so; disc a flat ring, glabrous to marginally hairy with simple hairs, marginally also with protruding trichomes ; pistil 2- or 3-locular, one ovule per locule, smooth, tomentose; style absent to short, stigmas apically not to slightly split, papillate above, tomentose below. Fruits lobed c. obcordate capsules, leathery, thin-walled, loculicidal, hardly septicidal, densely hairy outside, glabrous inside; column usually dehiscing too, when present narrow, tapering towards the not or hardly broadened apex; septa remnants with a single vein, narrow, straight, non-fibrous. Seeds usually 2 or 3 per fruit, triangular in transverse section, adaxially with sharp ridge, abaxially convex, covered by a thin, fleshy sarcotesta; exotesta thin, smooth, mesotesta woody, mesotesta and endotesta folding inwards.

    Distribution — Two species, one restricted to Cambodia (Kampuchea), the other widespread from Peninsular Thailand throughout Malesia and into the Pacific to Taiwan, Ryukyu Islands, and Society Islands.

    Note — The two species can be separated by the dentation of the leaves, whereby M. vitifolia is obscurely dentate and always 3-palmatifid, while M. multiglandulosa has very coarse teeth, and is usually not lobed and when lobed only in juvenile stages until about halfway along the blade (mainly on Okinawa). The other characters mentioned by Gagnepain (1925) are incorrect (number of styles) or could not be verified (difference in dehiscence, M. vitifolia dehiscing very tardily).

 

Melanolepis multiglandulosa (Reinw. ex Blume) Rchb.f. & Zoll.

 

    Melanolepis multiglandulosa (Reinw. ex Blume) Rchb.f. & Zoll., Acta Soc. Regiae Sci. Indo-Neerl. 1 (1856) 22; Linnaea 28 (1856) 324; Merr., Interpr. Herb. Amboin. (1917) 318; Sp. Blancoan. (1918) 223; Enum. Philipp. Fl. Pl. (1923) 431; Corner, Ways. Trees Malaya (1940) 274, text-fig. 87; Holthuis & H.J.Lam, Blumea 5 (1942) 203; Backer & Bakh.f., Fl. Java 1 (1964) 481; Airy Shaw, Kew Bull. 26 (1972) 309; Whitmore, Tree Fl. Malaya 2 (1973) 118; Airy Shaw, Kew Bull. Add. Ser. 4 (1975) 175; Kew Bull. Add. Ser. 8 (1980) 174; Kew Bull. 36 (1981) 332; Kew Bull. 37 (1982) 30; Alph. Enum. Euphor. Philipp. Isl. (1983) 38; Welzen et al., Blumea 44 (1999) 439, Fig. 1, Map 1; Welzen in Welzen & Chayam., Fl. Thailand 8, 2 (2007) 44, Fig. 42. — [Croton multiglandulosus Reinw. ex Blume, Catalogus (1823) 105, nom. nud.] — Rottlera multiglandulosa Reinw. ex Blume, Bijdr. (1825) 609. — Mallotus multiglandulosus (Reinw. ex Blume) Hurus., J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6 (1954) 308. — Lectotype (Welzen et al., 1999): Anonymous s.n., s.d. (L, holo, barcode L 0020491), Java.

    Ricinus dioicus Wall. ex Roxb., Fl. Ind. 3 (1832) 690; Wall., Numer. List (1847) 7808. — Melanolepis ? calcosa Miq., Fl. Ned. Ind. 1(2) (1859) 399, nom. superfl.Mallotus calcosus (Miq.) Müll.Arg. in DC., Prodr. 15.2 (1866) 958, nom. superfl.Rottlera calcosa (Miq.) Scheff., Ann. Mus. Bot. Lugduno-Batavum 4 (1869) 125, nom. superfl. — Lectotype (Welzen et al., 1999): Rumphius, Fl. Amb. 4 (1743) t. 64: Folium calcosum. See note 2.

    Adelia monoica Blanco, Fl. Filip., ed. 2 (1845) 561; Merr., Sp. Blancoan. (1918) 223 (under Melanolepis multiglandulosa). — Neotype (Welzen et al., 1999, see Merrill, 1918): Merrill Species Blancoanae 489 (NY, holo, n.v.; iso in BO, L), Philippines, Luzon, Manila.

    Melanolepis angulata Miq., Fl. Ned. Ind., Eerste Bijv. (1860) 455. — Mallotus angulatus (Miq.) Müll.Arg. in DC., Prodr. 15, 2 (1866) 958. — Rottlera angulata (Miq.) Scheff., Ann. Mus. Bot. Lugd.-Bat. 4 (1869) 124. — Type: Diepenhorst s.n. (holo U?, n.v.), Indonesia, Sumatra, Priaman Prov.

    Mallotus moluccanus (L.) Müll.Arg. var. glabratus Müll.Arg. in DC., Prodr. 15, 2 (1866) 958. — Melanolepis multiglandulosa (Reinw. ex Blume) Rchb.f. & Zoll. var. glabratus (Müll.Arg.) Fosberg, Phytologia 5 (1955) 289. — Syntypes: Gaudichaud 181 (n.v.); Wallich 7808 (K); 7826B (K).

    Mallotus hellwigianus K.Schum. in K.Schum. & Hollrung, Fl. Kaiser. Wilh. Land (1889) 79. — Mallotus hollrungianus T.Durand & B.D.Jacks., Ind. Kew., Suppl. 1 (1906) 262, nom. superfl. — Type: Hollrung 412 (n.v.), Papua New Guinea, Hatzfeldthafen.

    Mallotus moluccanus (L.) Müll.Arg. var. pendulus Merr., Philipp. J. Sci. 7 (1912) 401. — Melanolepis moluccanana (L.) Pax & K.Hoffm. var. pendula (Merr.) Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii (1914) 144 — Melanolepis multiglandulosa (Reinw. ex Blume) Rchb.f. &Zoll. var. pendulus (Merr.) Merr., Enum. Philipp. Fl. Pl. (1923) 432 — Lectotype (Welzen et al., 1999): Merrill 8305 (PNH, †, n.v.; iso in L), Philippines, Mindanao, District of Zamboanga.

    Mallotus moluccanus auct. non. (L.) Müll.Arg.: Müll.Arg., Linnaea 34 (1865) 185; in DC., Prodr. 15.2 (1866) 958. — Mallotus moluccanus sensu Müll.Arg. var. genuinus Müll.Arg., Linnaea 34 (1865) 185, nom. inval.Rottlera moluccana Scheff., Ann. Mus. Bot. Lugduno-Batavum 4 (1869) 122 — Melanolepis moluccana (L.) Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.vii (1914) 142, fig. 20. See note 3.

 

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Shrub to tree, up to 20 m high, d.b.h. up to 30(–60) cm, in monsoon areas deciduous; flowering twigs 2–11 mm thick. Indumentum off-white, light grey, grey-yellow or brown hairs. Bark smooth to shallowly longitudinally fissured with many minute lenticels, mainly in the fissures, to finally flaky, flakes detaching easily, grey to (mottled) pale fawn-grey to light grey-brown, to pale yellow, up to 3 mm thick; under bark green to dark straw to blue grey under lenticels; inner bark firm, fibrous, whitish to green to pale yellow to (orange-)brown, turning dark blue after exposure, c. 6 mm thick; latex sometimes obvious, milky, sticky; wood soft, cream to pale straw to greenish. Stipules c. 1.2 by 0.8 mm. Leaves: petiole 2.4–31 cm long, whitish when dry; blade ovate, sometimes 3-lobed, 5–38 by 5–34 cm, index 1–1.1, smooth, dull light to dark green above, paler, whitish to almost glaucous, more glossy below, midrib and veins often whitish at both sides, flat to slightly raised above, raised below. Inflorescences densely pale brown hairy; up to 26(–54) cm long, side-branches up to 41 cm long, often somewhat flattened. Bracts 1.4–2.5 by 0.5–1 mm, thick; bracteoles 0.5–0.6 by 0.4–0.5 mm. Staminate flowers 7–13 mm in diam.; pedicels 5–6 mm long, abcission zone in upper 2–3 mm, often inconspicuous; sepals pale grey to (yellowish) white, grey green inside; stamens cream-white to (pale) yellow, filaments 1.5–2.3 mm long, anthers 0.8–1 by 0.5–0.6 mm. Pistillate flowers 4.5–5.5 mm in diam.; pedicels 3–6(–13 in fruit) mm long with (inconspicuous) abscission zone in upper 0.5–1.5(–3.5 in fruit) mm; calyx (brownish) mid green to yellowish to white, tube c. 1 mm high, lobes 1.7–3 by 1.2–1.8 mm; ovary 2.5–3.8 by 3.3–4.2 mm wide, light green; style almost absent to 0.6(–2) mm long, stigmas c. erect, creamy, up to 1.1 mm long, when split only upper c. 0.5 mm split. Fruits 9–15 by 7–9 mm, densely tomentose with stellate hairs to almost glabrous, mid green to greenish brown to olive green to greyish green; column c. 5 mm long, cream. Seeds 5.5–6 by 4.5–5.5 mm, creamy to purplish margenta; aril grey to orange.

    Distribution — Taiwan, Ryukyu Islands, Marianas, from S Thailand throughout Malesia to Papua New Guinea (Bismarck Archipelago). Unknown from Sarawak and Brunei on Borneo.

 

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    Habitat & Ecology — Rare to usually locally common, mainly found in secondary places like roadsides, regrowth thickets, depleted open secondary forest, forest edges in savannah, coconut plantations, old gardens, but also in primary forest, (Barringtonia) swamp forest, Eucalyptus deglupta dominated forest, monsoon (deciduous) forest, along mangroves. Considered an invader of cut forest (Ryukyu Isl.: Walker & Tawada 6624). Soil, often poorly drained and/or temporary inundated: alluvial sand, clay, vulcanic soil, coral (sand), red loam; Andesite bedrock. Altitude: sea level up to 300(–1335) m. Flowering and fruiting throughout the year. The seeds are eaten by birds [Lae (Wiakabu & A.M.C.) 73584].

    Uses — Japan (Ryukyu Islands): Wood is used for shoes. Borneo, Sabah: Bark used as a cure for cough. Philippines: Use against chest pain and leaves or flowers on wrist against fever. Moluccas, Ceram: counter poison (not indicated against what; Eyma 3425). Also suitable as firewood (Philippines, Papua New Guinea).

    Notes 1. The species is somewhat variable in its range, towards the north (West Pacific Islands) and to the east (Bismark Archipelago) there is a tendency to more glabrous leaves, while in New Guinea two basal glands at the upper surface protrude further than the other glands and at the lower surface there are always two basal black glandular areas. The latter are usually absent in specimens from other areas.

2. Usually, the name Ricinus dioicus is attributed to Wallich and is always cited as R. dioicus Wallich ex Roxb. However, Roxburgh did only refer to the text and plate in Rumphius’s book and cited Ambon as the place of origin of the material. Roxburgh’s Flora Indica (1832) was published after his death and was edited by Wallich. The identificaton of a specimen collected by Wallich (Wallich 7808) was only published in 1847, in a later edition of the Flora Indica. Therefore, it is likely that by the time the Flora was published, Wallich had not yet collected Melanolepis and, consequently, the plate of Rumphius (which can easily be identified as M. multiglandulosa) has to be selected as type. Selecting Rumphius’s plate as lectotype reduces Melanolepis calcosa Miq. (and the names based on it) to superfluous homotypic synonyms of Roxburgh’s name.

3. The name Croton moluccana L., to which Müller Argovius, Pax & K.Hoffmann, and Scheffer refer in their new combinations, is based on two references. The first one (‘Fl. Zeyl. 346’; must be page 146) is Givotia rottleriformis, the other one (‘Nux juglans moluccana bifida Burm. Fl. Zeyl. 170’) is Aleurites moluccana (the latter is based on Jatropha moluccana L., by coincidence the same epithet). The specimen in Linnaeus’s herbarium (no. 1140/20) in London is indeed M. multiglandulosa, but this is not the type of the species (Merrill, 1917; Trimen, 1898). Müller Argovius regarded this specimen as the type and, therefore, erroneously made the necessary combination in Mallotus. The best thing to do is to lectotypify Linnaeus’s name with one of the Hermann specimens (Givottia rottleriformis), because this is the only indirect reference (via L., Fl. Zeyl.) to specimens; the other reference only mentions the description in Burman’s Thesaurus Zeylanica (= Aleurites moluccana).