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

Pterygota horsfieldii (R.Br.) Kosterm.

Reinwardtia Vol. 2: 365 (1953)

Family: Malvaceae
Dicotyledon

Timber Group: Non-timber species

Field Characters: Large canopy tree (up to c. 30 m high) or Small sub-canopy tree; Bole cylindrical (up to c. 100 cm diam.); straight (bole up to 20 m long); buttresses buttresses present; spines spines absent; aerial roots aerial roots absent; stilt roots stilt roots absent; Bark pale red, brown, or grey (pale mottled), smooth or slightly rough, slightly cracked; Subrhytidome (under-bark) yellow (pale (straw-coloured) or white; less than 25 mm thick; bark blaze consisting of one layer; faintly to non-aromatic; outer blaze yellow (pale (straw-coloured) or white, with stripes (pale brown); inner blaze yellow (pale (straw-coloured) or white, with stripes (pale brown); bark exudate (sap) absent; terminal buds not enclosed by leaves.

Indumentum: Complex hairs present, star-like (stellate); stinging hairs absent; mature twig indumentum (hairs) present when young or soon absent, hairs usually sparse.

Leaves: Leaves clustered at end of branches to spaced along branches, spiral (leaves occurring singly at a node and arranged spirally up the branchlet), simple (a leaf composed of a single blade); petiole present, not winged, attached to base of leaf blade, swollen (slightly (at base) to not swollen; leaves broadest below middle, 14.0-24.0 cm, 9.5-20.0 cm; symmetric, entire, not dissected or lobed, obtuse or sub acuminate, venation pinnate, secondary veins open, prominent, intramarginal veins absent; leaves lower surface green, upper surface dull dark green, indumentum (hairs) usually absent or occasionally present, indumentum (hairs) sparse; absent; domatia absent; stipules present, free, laterally placed, not encircling the twig, leafy, not fringed, large (c. 3 mm long), not persistent.

Flowers: Inflorescence axillary, on the trunk or branches, or sub terminal, flowers on a branched axis, cones absent; flowers unisexual, unisexual with male and female flowers on the same plant, stalked, flowers with many planes of symmetry, 12.0-15.0 mm long, diameter small (up to10 mm diam.) (c. 10 mm diam.); perianth present, with all sepals and/or petals (hence tepals) similar, inner perianth brown (pale (densely covered with reddish brown hairs) or dull red; 5, some or partly joined (forming almost subfleshy perianth tube and 5 lobes); stamens 25 (c. (in groups of 5 - male flowers; sterile anthers - females flowers), absent, joined (to form a staminal column), free of the perianth; ovary superior, carpels partially joined, by base, locules 5; styles absent.

Fruits: Infrutescence arranged on branched axis, fruit 70.0-80.0 mm long, 60.0-70.0 mm diam., brown or red, not spiny, non-fleshy, simple, dehiscent, follicle (opening by one slit); seeds 100, about 10 mm long (12-15 mm long, excluding wing) or much more than 10 mm long (c. 60 mm long, including wing), winged (with a single wing 40-45 mm long), broad (as wide as long) (slightly flattened), seed 1-10 mm diam. (c. 10 mm diam.).

Distribution: Madang, Western, Gulf, Central, Northern, Milne Bay & Bougainville.

Botanical records in PNGplants database Map details

Notes: Notes The genus Pterygota was previously classified in the family Sterculiaceae.