A revision of the Nasa ranunculifolia group (Nasa ser. Grandiflorae pro parte, Loasaceae)

The monophyletic Nasa ranunculifolia group (Nasa ser. Grandiflorae pro parte) is revised on the basis of extensive field studies and a revision of copious herbarium material. All species of this group are from the high Andes of Peru and Ecuador (mostly 3000-4300 m). The overall degree of morphological divergence is much lower than in other groups of Nasa and many of the various local 'races' are best recognized as ecogeographically isolated subspecies. Thus, six species and 13 subspecies are recognized on the basis of differences in leaf and floral morphology, growth habit, life history and distribution. Nasa ranunculifolia, N. macrantha, N. cymbopetala and N. macrorrhiza are united as subspecies under N. ranunculifolia. An additional five subspecies of N. ranunculifolia are newly described (ssp. pamparomasii, ssp. guzmangoensis, ssp. bolivarensis, ssp. patazensis and ssp. huanucoensis). Nasa rugosa is subdivided into four subspecies, three of them new (ssp. llaqtacochaensis, ssp. gracilipes and ssp. pygmaea). Nasa tulipadiaboli sp. nov. and N. basilica sp. nov. are described as new species. Eight taxa (seven subspecies and one species) are endemic to the Amotape-Huancabamba Zone, and seven of them (six subspecies and one species) are new to science. Only a single species ranges into the Amotape-Huancabamba Zone from the south, underscoring the high levels of endemism (and taxonomic novelty) in this area. Illustrations, distribution maps, a key and diagnoses are given for all taxa recognized. (C) 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167, 47-93.