PNGTreesKey – Mastixiodendron plectocarpum S.P.Darwin


Barry Conn (NSW) & Kipiro Damas (LAE).
Guide to trees of Papua New Guinea
Copyright held by the authors, National Herbarium of New South Wales, and Papua New Guinea National Herbarium

Mastixiodendron plectocarpum S.P.Darwin

Journal of the Arnold Arboretum Vol. 58(4): 370 (1977)

Family: Rubiaceae

Timber Group: Non-timber species

Field Characters: Small sub-canopy tree or Large canopy tree (up to 35 m high); Bole cylindrical (up to 60 cm diam.); straight (bole up to 25 m long); buttresses buttresses absent or buttresses present (buttresses up to 1.5 m high); spines spines absent; aerial roots aerial roots absent; stilt roots stilt roots absent; Bark brown or dark grey, slightly rough or smooth, scaly or flaky or fissured; less than 25 mm thick; bark blaze consisting of one layer; faintly to non-aromatic; outer blaze pale yellow or white, markings absent; inner blaze pale yellow or white, markings absent; bark exudate (sap) present, colourless, not readily flowing (spotty), sticky or not sticky; terminal buds enclosed by leaves.

Indumentum: Complex hairs absent; stinging hairs absent; mature twig indumentum (hairs) absent.

Leaves: Leaves spaced along branches, opposite (in pairs, opposite one another on the branchlet), simple (a leaf composed of a single blade); petiole present, not winged, attached to base of leaf blade, not swollen; leaves broadest below middle or broadest at or near middle, 6.0-19.0 cm, 1.5-6.5 cm; symmetric, entire, not dissected or lobed, rarely acuminate or sub acute, venation pinnate, secondary veins open, not prominent, but visible, intramarginal veins absent; leaves lower surface green, upper surface green (sub-glossy), indumentum (hairs) absent; absent; domatia absent; stipules present, joined, joined across twigs (slightly twisted), not encircling the twig or almost encircling the twig, leafy, not fringed, large (12-20 mm long), not persistent.

Flowers: Inflorescence axillary, flowers on a branched axis, cones absent; flowers bisexual, stalked, flowers with many planes of symmetry, (6.0-) 8.0-11.0 mm long, diameter small (up to10 mm diam.) (5-12 mm diam.); perianth present, with distinct sepals and petals whorls, inner perianth yellowish green or pale yellow; 4, free; stamens 4, present, free of each other, free of the perianth; ovary inferior, carpels joined (when more than one), locules 2; styles solitary, 1.

Fruits: Infrutescence arranged on branched axis, fruit (20.0-) 25.0-30.0 mm long, 10.0-16.0 mm diam., black when mature or pale green, not spiny, fleshy, simple, indehiscent, drupe; seeds 1, about 10 mm long (10-12 mm long), not winged, narrow (longer than wide), seed 1-10 mm diam. (2-3 mm diam.).

Distribution: West Sepik or Western.

Mastixiodendron plectocarpum
Botanical records
in PNGplants database

Map details


Notes: Notes S.P. Darwin (1977), in Journal of the Arnold Arboretum, volume 58, pp. 349-381 describes this species from Geelvink Bay of West New Guinea (West Papua) amd the Western region of Papua New Guinea. One collection, D.B. Foreman and M. Kumul NGF48218, from the West Sepik region is here regarded as possibly also belonging to this species.