Monoon in Melanesia

Turner, Ian M. & Utteridge, Timothy M. A., 2017, Annonaceae in the Western Pacific: geographic patterns and four new species, European Journal of Taxonomy 339, pp. 1-44 : 2-3

Monoon in Melanesia

The generic name Monoon was recently taken up again ( Xue et al. 2012) for a group of 60–70 species, mostly formerly included in Polyalthia , Enicosanthum , Cleistopetalum and Woodiellantha . The genus has not been monographed, but in listing the species that they recognised in the genus and making many new combinations, Xue et al. (2012) included three species from New Guinea: Monoon chloranthum (Lauterb. & K.Schum.) B.Xue & R.M.K.Saunders , Monoon chloroxanthum Miq. and Monoon polycarpum (Burck) B.Xue & R.M.K.Saunders. In going through the material of Monoon from New Guinea and the Solomons, it became obvious to us that more species were present than these three. One group of specimens with very thick, fleshy petals clearly differed from the described taxa which all have relatively thin petals. The fleshy-flowered group included a New Guinea gathering distributed as Polyalthia pachypetala Diels. However , this name appears never to have been published. The thick- petaled specimens from the Solomons differ significantly from the New Guinea material, so we describe both as new. There is possibly a third species with fleshy petals represented by a specimen from New Britain (NGF 22441), but the material is too limited to describe.

We consider these species to belong in Monoon due to the possession of eucamptodromous leaf venation, decurrent insertion of lateral nerves to the midrib, uniovulate carpels and (where available) relatively soft seeds with an irregular longitudinal groove and lamelliform endosperm quartering the seed in transverse section.