Medium to tall trees. Leaves opposite and decussate, imparipinnate, up to 6-jugate, with lateral leaflets subopposite; Stipules 4 per node, lateral, ± foliaceous with main vein asymmetrically placed, leaving 2 contiguous interpetiolar scars on either side between adjoining leaf bases. Inflorescences terminal or axillary, paniculate, many-flowered, with terete branches and small caducous bracts, the branching varying from decussate in major branches through subopposite to ± spirally arranged in ultimate branchlets. Flowers bisexual, (4-)5(-6)-merous (except gynoecium), shortly pedicellate. Sepals valvate, subcoriaceous. Petals shorter than sepals, membranaceous, cuneate, bifid, with small glands at the apices. Stamens with subulate-terete filaments and oval to cordate anthers. Ovary superior, syncarpous, 3(-4)-carpellate, each cell with a free subulate style and 2 or (3-)4 ovules. Fruit indehiscent, a 3(-4)-winged samara, obcordate in outline, the apex deeply incised, each wing formed by lateral expansion of the carpel wall; Seeds oblong, the surface minutely papillate.
Asia-Tropical:, New Guinea ‒ present Australasia: NE Queensland: present
3 species, 2 in Australia (NE Queensland) and 1 in Malesia: New Guinea.
1 The Malesian species is quite similar to G. adenopetala F.Muell. from Australia, the most reliable distinguishing character being the number of ovules per locule (4, occasionally 3 in G. adenopetala; 2 in G. papuana). Both the Australian species also differ in having ciliate petals, somewhat larger flowers, a glabrous ovary (though tomentum may develop in young fruit of G. whypallana Rozefelds & Pellow), and terminal inflorescences, and the margin of leaflets is usually toothed or crenate (not entire), but none of these differences is fully diagnostic. 2. Schlechter (1914) illustrated the stipules in G. papauana as interpetiolar, with one pair per node, but this appears to be an error (and see discussion in Rozefelds & Pellow 2000).