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Malesian Euphorbiaceae Descriptions |
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Welzen, P.C. van & P.I. Forster. 2012. Five rare genera of Euphorbiaceae (sensu lato) in the Malay Archipelago: Alphandia, Ashtonia, Borneodendron, Cladogynos and Tapoïdes. Edeninburgh J. Bot. 69: 389–411.
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Alphandia Baill., Adansonia 11 (1873) 85; Pax & K.Hoffm. in Engl., Pflanzenr. IV.147.iii (1911) 22; Airy Shaw, Kew Bull. 20 (1967) 395; Kew Bull., Addit. Ser. 4 (1975) 8, 10, key; Kew Bull., Addit. Ser. 8 (1980) 27; McPherson & Tirel, Fl. Nouvelle-Calédonie 14 (1987) 86; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 109; Govaerts, Frodin & Radcl.-Sm., World Checkl. Bibliogr. Euphorb. 1 (2000) 155; Radcl.-Sm., Gen. Euphorbiacearum (2001) 311; Welzen, Edinburgh J. Bot. 69 (2012) 390; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 172. — Lectotype (designated by McPherson & Tirel, 1987): Alphandia furfuracea Baill. [lectotypification probably unintentional, but valid and followed by Webster (1994) and Radcliffe-Smith (2001)].
Shrubs to trees, monoecious; latex yellowish or red. Indumentum of stellate to somewhat lepidote hairs (see note 2). Stipules absent. Leaves alternate (to subopposite at apex of twigs), simple, long petiolate, symmetric, coriaceous, base with two single or pairs of glands near the attachment, margin entire, apex rounded to acuminate, with one or two glands, both surfaces smooth, upper (sub)glabrous, lower densely hairy, no epidermis visible except above the venation, penninerved, raised on both surfaces, nerves ending in marginal vein (New Guinea) or looped and merging together near the margin (Vanuatu, New Caledonia), , veins ± scalariform, veinlets densely reticulate. Inflorescences paniculate thyrses with basally short to long side branches with few-flowered cymes to apically single flowers per node, unisexual or bisexual, when latter then pistillate flowers basal to staminate flowers; flowers with two buds per petiole and an abscission zone above the buds, branches hairy; bracts triangular, minute. Flowers 5-merous, actinomorphic; pedicel round, hairy; calyx cupular, 5-lobed till halfway, valvate; disc annular, glabrous. Staminate flowers yellow; petals 5; stamens many, filaments of outer ones recurved, of inner ones united, anthers sub-basally dorsifixed, geniculate on abaxially thickened connective, thecae on front of connective, 2, pointing outwards, opening extrorse via lengthwise slits; pistillode absent. Pistillate flowers green; petals absent or 5 but caducous; ovary obovoid, densely hairy, later varnished (by nectar?), 3-locular, wall thick, a single ovule per locule; style short; stigmas 3, each completely divided into 2 triangular lobes, glabrous and smooth above. Fruits (Radcliffe-Smith 2001) ellipsoid-globose, smooth, dehiscing into 3 2-valved parts or 6 valves, wall woody; column long, apically with c. 5 vein remnants per locule. Seeds (Radcliffe-Smith 2001) ellipsoid-cylindric, apiculate, carunculate; testa marbled.
Distribution — A genus of three known species, one from New Caledonia, one from New Caledonia and Vanuatu and one from Indonesian New Guinea. The generic distribution may be explained by dispersal from the Inner Melanesian Arc, of which New Caledonia was part and which existed till the Pliocene (2-5 Ma), to the Outer Melanesian Arc of which Vanuatu and the northern coast of New Guinea were part.
Habitat & Ecology --- In New Caledonia in maquis on serpentine soil; in New Guinea recorded from selectively logged primary forest on lateritic clay.
Notes — 1. Classified by Webster (1994) and Radcliffe-Smith (2001) in subfam. Crotonoideae tribe Ricinocarpeae subtribe Ricinocarpinae together with Beyeria and Ricinocarpos (according to Govaerts et al., 2000, ‘a somewhat odd move and ultimately largely related to pollen form’). The exact relationships of the genus are still unknown as was also discussed by Airy Shaw (1966).
2. Radcliffe-Smith (2001) notes the presence of glands or minute scales exuding resinous or verniciform sap. I could not find these scales or glands. As far as I can judge the basal and apical gland(s) of the leaves are the only excuding spots.
Alphandia verniciflua Airy Shaw, Kew Bull. 20 (1967) 395; Kew Bull., Addit. Ser. 8 (1980) 27; Welzen, Edinburgh J. Bot. 69 (2012) 391, Fig. 1. — Type: Versteegh BW 4815 (holo L; iso A), (Indonesia, Papua,) Hollandia [Jayapura], Noordwijk.
Trees, up to 18 m high; twigs c. 4 mm in diameter, slightly angular, glabrescent. Indumentum of short stellate to somewhat lepidote hairs (partly fused radii). Leaves: petiole 2.5–7.2 cm long, hardly thickened basally and apically, basally round to adaxially flattened or grooved apically, (sub)glabrous, varnished; blade elliptic to slighty obovate, 5.7–18 by 3.1–11 cm, length/width ratio 1.6–1.8, base cuneate, with 2 obscure to distinct glands near the attachment, margin slightly recurved, apex acute to slightly acuminate, tip rounded to slightly emarginate, with two glands, each on a side of the midrib, sometimes seemingly one gland, upper surface glabrous, varnished, lower surface not hairy on venation (but young leaves probably are, stalk remnants of hairs present above veins), venation with distinct marginal nerve and 7–10 nerves ending in the marginal nerve. Inflorescences up to 18 cm long, with the longest side branch up to 9.5 cm long; bracts c. 1 by 1 mm, outside hairy, inside glabrous; bracts 0.7–1 mm long, hairy outside, glabrous inside. Staminate flowers c. 5.5 mm in diameter; pedicel c. 5.4 mm long; calyx c. 1.3 mm high, coriaceous, lobes triangular, c. 0.7 by 0.6 mm; petals 5, obovate-oblong, c. 3.2 by 1.7 mm, thin, margins inrolled, apex obtuse, glabrous; stamens c. 30; filaments c. 1 mm long; anthers c. 0.3 by 0.3 mm. Pistillate flowers 2.8–3.5 mm in diameter; pedicel c. 5.5 mm long; sepal lobes c. 1.3 by 1.3–1.5 mm; petals absent; ovary obovoid, 1.5–2.3 by 1.5–2.3 mm; style c. 0.8 mm long, stigma lobes c. 0.7 mm long. Fruits and seeds unknown.
Distribution — Known from two specimens only, seemingly endemic in Indonesian New Guinea (Prov. Papua, formerly Irian Jaya) around Jayapura (formerly Hollandia).
Habitat & Ecology — Recorded from selectively logged primary forest on lateritic soil; altitude: c. 25 m. Flowering: September, October.
Note — Alphandia verniciflua can easily be distinguished vegetatively from the other two species from New Caledonia and Vanuatu; A. verniciflua is a tree (instead of shrubs), with a glabrous abaxial venation and the nerves ending in the marginal nerve (hairy veins in the other species with the nerves looped and connected near the margin, not ending in a marginal vein), and usually two apical leaf blade glands (instead of one). In flower A. verniciflua has smaller calyx lobes and lacks petals in the pistillate flowers.
