Annual to perennial climbers with up to 6 m long, herbaceous shoots and monoecious sex system. The leaves are simple, petiolate, with entire or lobed, elliptic to hastate blade. The tendrils are simple. The flowers are small to medium-sized. Male flowers are produced in pedunculate racemes or solitary, the female flowers stand solitary. The receptacle-tube is shallow, cup-shaped or urceolate to campanulate with five minute sepals. The corolla is 10-15 mm across with five, free, entire, cream-coloured, yellow or orange petals, aestivation imbricate. The three stamens are free, inserted halfway up the tube on long, slender or rarely short filaments. The anthers are all bithecous, free, but often appressed into a subglobose head. The thecae are straight, curved or sigmoid and contain tricolporate, striate-reticulate, small pollen (polar axis 31-38 µm, equatorial axis 32-38 µm (Duyfjes et al. 2003, van der Ham & Pruesapan 2006)). The ovary is subglobose or ellipsoid to fusiform with many, horizontal ovules. The style is trilobed, papillose-hairy or with forked and feather-like divided stigma-lobes. The fruit is an edible, juicy berry, globose to ellipsoid-oblong, to 3 cm long and 1.5 cm across, glabrous, ripening scarlet to glossy red. The many seeds are tumid to globose, ovoid. The testa is cream-coloured to pale brown, finely scrobiculate or foveolate, sometimes with narrow margin.
The seven species grow in (disturbed) montane Nothofagus forest, along forest margins, among tree ferns, in low scrub, in lowland swamp forest and on river banks in New Guinea.
Phylogenetically, the genus is placed in Benincaseae, where it is sister to Scopellaria (Schaefer et al. 2009, Schaefer & Renner 2011).
Papuasicyos arfakensis (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Papuasicyos belensis (Merr. & L.M. Perry) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Papuasicyos carrii (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Papuasicyos hippocrepicus (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Papuasicyos papuanus (Cogn.) Duyfjes, Blumea 48: 124. 2003.
Papuasicyos parviflorus (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Papuasicyos viridis (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner, Taxon 60: 134. 2011.
Duyfjes, B.E.E., van der Ham, R.W.J.M. and W.J.J.O. de Wilde. 2003. Papuasicyos, a new genus of Cucurbitaceae. Blumea 48: 123-128.
De Wilde, W.J.J.O. and B.E.E. Duyfjes. 2006. Redefinition of Zehneria and four new related genera (Cucurbitaceae), with an enumeration of the Australasian and Pacific species. Blumea 51: 1-88.
Schaefer, H. and S.S. Renner. 2011. Phylogenetic relationships in the order Cucurbitales and a new classification of the gourd family (Cucurbitaceae). Taxon 60: 122-138.
Schaefer, H., Heibl, C., and S.S. Renner. 2009. Gourds afloat: a dated phylogeny reveals an Asian origin of the gourd family (Cucurbitaceae) and numerous oversea dispersal events. Proceedings of the Royal Society B 276: 843-851.
Van der Ham, R.W.J.M., Pruesapan, K. 2006. Pollen morphology of Zehneria s. l. (Cucurbitaceae). Grana 45: 241–248.