Gyrocarpus americanus
Description
Tree 3-30 m high, dbh 20-100 cm, trunk smooth or with coarse scales, pale grey or nearly white.
Leaves: petiole 4-19.5 cm long; leaf-blade coriaceous or chartaceous, entire, or in young trees with 3 or 5 acute lobes, cordate to ovate, 7-24 by 4-21 cm, base cordate to broadly rounded to cuneate, apex c. 1 cm acuminate, pubescent on both surfaces or the upper surface glabrous, nerves conspicuous, 3- or 5-palminerved, with ladder-like tertiary veining.
Inflorescence (including 3-6 cm long peduncle) 5-17 cm long, the flowers compact, all parts more or less pubescent.
Flowers 4-merous, small (mature bud less than 1.5 mm diam.), bisexual and unisexual (only male flowers), pale green or creamy; filaments in female flowers c. 1.5 mm long, in male flowers c. 2 mm long with 4 alternating small glands, 0.5-1 mm long.
Fruits: nut ovoid, 1.4-2 by 0.8- 1.3 cm, longitudinally 8-ribbed, topped with a pair of spathulate wings, 6.5-9 cm long, 2-3 mm wide at base, 0.8-1.1 cm wide at widest part, resembling those of certain dipterocarps, yellowish green; the whole fruit thinly up to thickly pubescent, seldom glabrous.
Distribution
Asia-Tropical: Lesser Sunda Is. present; Malaya (Peninsular Malaysia present); Philippines (Philippines present), E Java present, Pantropical present, around Port Moresby present, in Ramu Valley present
Pantropical, in regions with a monsoon climate; in Malesia: Peninsular Malaysia, E Java, Philippines, Lesser Sunda Islands, Papua New Guinea (around Port Moresby and in Ramu Valley)
Morphology
Branches ascending with drooping branchlets. Slashed wood with creamy or yellowish exudate; bruised tissue with unpleasant smell. Frequently mentioned as flowering or fruiting while the tree is leafless. The leaves are convex at the time they are falling off. According to Merrill Sp. Blanc. 755, the species is in the Philippines widely distributed, but nowhere abundant.
Taxonomy
Kubitzki (1969) distinguished 7 subspecies in G. americanus on characters of outline and hair-covering of the leaves, with in the Malesian area 2 subspecies: subsp. americanus, occurring in the whole area, and subsp. sphenopteris (R.Br.) Kubitzki in the Lesser Sunda Islands (Sumbawa) and the Philippines (Luzon). More field observations are needed to clarify the position of these taxa.
Citation
Backer & Bakh.f 1964 – In: Fl. Java: 136
Du Puy & Telford 1993 – In: Fl. Austral.: 72.
Kubitzki 1969 – In: Bot. Jahrb.: 182
Ridley 1924 – In: Fl. Malay Penins.: 139.
Ng 1973: p. 244. – In: Tree Fl. Malaya: f. 1.
Merr. 1923 – In: Enum. Philipp. Flow. Pl.: 205
Merr. 1918: Sp. Blanc.: 155.
Croft 1981: p. 191. – In: Handb. Fl. Papua New Guinea: f. 42
A.C. Sm. 1981: p. 143. – In: Fl. Vit. Nov.: f. 46