Blumeodendron borneense Pax & K.Hoffm.

1. Blumeodendron borneense Pax & K.Hoffm. View in CoL — Fig. 1 View Fig ; Map 1

Blumeodendron borneense Pax & K.Hoffm. (1919) View in CoL 14; Airy Shaw (1975) 58. — Blumeodendron tokbrai (Blume) Kurz var. borneense (Pax & K.Hoffm.) J.J.Sm. ex Airy Shaw (1981) View in CoL 269. — Type: Beccari PB 2976 (FI not seen; iso K), Borneo.

Blumeodendron concolor Gage (1922) View in CoL 244; Ridl. (1924) 281; Airy Shaw (1975) 59. — Type: Curtis KD 1368 (K), [Malay Peninsula,] Pangkor.

Blumeodendron sp. : Merr. (1929) 157. — pro Elmer 21129 ( L), British North Borneo [= Sabah], Tawao .

Blumeodendron tokbrai auct. non (Blume) Kurz: Airy Shaw (1975) 60, p.p., ‘form with oblong leaves’.

Trees, up to 35 m high, bole to 15 m high, dbh to 30 cm (– 2 m); buttresses sometimes present, few, c. 1 m high, c. 0.3 m out, c. 20 cm thick; stem generally round, nodes notably thickened; lenticels indistinct, round; flowering branches 5–28 mm thick, terminal ones often triangular of flattened in section; distance between internodes c. 18 cm; sympodial growth via axillary buds obvious. Outer bark tan to reddish brown, to dark brown, whitish grey, (pale) grey to grey-brown dippled, smooth to rough to fissured and peeling off, brittle, c. 1 mm thick; inner bark white to pale yellow, orange, pale greenish, pale brown outside to yellow inside, c. 4 mm thick; sapwood white to pale yellow; heartwood reddish. Indumentum : simple hairs absent. Leaves in (pseudo-)whorls of 3 to alternate (see Notes 1, 2); petiole 0.7–10 cm long, diam of thinnest part 0.9–3 mm, shiny, basal pulvinus 1.1–3.4 mm diam; lepidote hairs present, older parts glabrous; blade ovate to elliptic (see Note 3), 6–40 by 2.7–21 cm, length/width ratio 1.7–3.2, pergamentaceous to subcoriaceous, symmetric, glabrous, smooth dark green, drying light green, base rounded to obtuse, margin recurved, apex acuminate to cuspidate, tip to 1 cm long, extrafloral nectaries c. 6–18 along midrib, c. 6–26 along margin, both sides smooth; venation slightly and partly raised above, secondary nerves 4–7 pairs, at c. 46° angle with midrib, tertiary nerves perpendicular to midrib and secondary nerves, not raised above, higher order nerves reticulate, not raised above. Inflorescences ramiflorous to axillary and terminal, flowers almost fasciculate when staminate buds young, pistillate inflorescences single, length unknown. Staminate flowers only known from one specimen, either as bud or withered: pedicel c. 19 mm long, round; sepals 3, ovate, c. 4 by 3 mm, completely reflexed; stamens many, anthers c. 0.9 by 0.9 mm. Pistillate flowers unknown. Fruits c. 3 per inflorescence, subglobose, basally slightly sulcate, capsular, 3.5–4.1 by 3.1–4.3 cm, yellow to brown, 2–3-locular, ripening from green to yellow, dry brown, surface somewhat knobbly, vein ridges c. 3; pedicels c. 2 cm long, up to c. 0.4 cm diam, abscission zone indistinct; margin slightly thickened; wall 1–2 mm thick; endocarp enclosing two or more seeds; stigmas usually persistent. Seeds bean-shaped, 2.1–2.3 by 1.4–2 by 1–1.1 cm, attached in middle of bean, covered by a thin sarcotesta, dirty white to yellowish, sweet, edible.

Distribution — Malay Peninsula (very rare, only type of B. concolor ) and Borneo.

Habitat & Ecology — In mixed dipterocarp lowland forest, secondary forest, alluvial forest, mossy forest, primary upper montane forest, often along water and on very wet (but not inundated) soil; soil on (sandy) clay, igneous derived sandy clay. Altitude: 25– 700 m. Flowering: January; fruiting: February–May, July, September, October, December.

Vernacular names — Kalimantan: Kapol utan; Simpul (Bassap Dayak); Sabah: Indalus (Dusun Kinabatangan),Tampoi (Malay).

Notes — 1. Quite typical for B. borneense are the light coloured twigs, of which the upper ones are flattened or triangular, the leaves that dry light green, especially the lower surface, the almost fascicled flowers ( one specimen in bud seen), and the thin-walled fruits (wall 2 mm at most). Blumeodendron borneense is mainly known from Borneo. In Borneo a group of specimens, B. tokbrai , dries dark green and resemble B. borneense , but the leaves are alternate to (sub)opposite and seldom in whorls of 3 (end of branches), the flowers are along rachises and the fruits are very thick-walled (c. 5 mm).

2. The type of B. concolor , Curtis KD 1368 (K) from the Malay Peninsula, strongly resembles B. borneense , as the leaves are of the same size, elliptic and also dry green, the flowers are in fascicles. However, the leaves are alternate. Another example of a specimen with leaves alternate (but close together) or in pseudo-whorls is a cultivated specimen from Borneo in the Bogor Botanical Garden, Gravendeel, de Wilde & Hovenkamp 521 (Kebun Raya IX.C.144). As the leaves in Bornean B. borneense can also be in pseudo-whorls B. concolor is regarded as a synonym of B. borneense .

3. Specimens from Sarawak, including the type, and Brunei have a tendency to show ovate leaves, those of Sabah and Kalimantan are elliptic .