Jaffrea, a new genus of Rhamnaceae endemic to New Caledonia, with notes on Alphitonia and Emmenosperma. Issue 4 (December 2015)

• Record Type: Journal Article
• Authors: Hopkins, H.; Pillon, Y.; Stacy, E.; Kellermann, J.
• Is Part Of: Kew bulletin. Volume 70:Issue 4(2015:Dec.)
• Page Start: 1
• Page End: 19
• Publication Date: 2015-12
• Subjects: Fiji -- morphology -- New Guinea -- Pacific -- phylogeny; Botany -- Periodicals; 580
• DOI: 10.1007/s12225-015-9593-6
• Languages: English
• ISSNs: 0075-5974

Abstract

Summary Molecular phylogenetic and morphological data show that two species of Rhamnaceae endemic to New Caledonia, Alphitonia xerocarpa andA. erubescens, are misplaced. They form a clade that is sister toEmmenosperma, and they differ fromAlphitonia s.s. in their indumentum, venation, lower leaf surface, flowers, fruits and seeds. Although morphologically closer toEmmenosperma, both their flowers and fruits are distinct from those ofEmmenosperma s.s., and so a new genus, Jaffrea H. C. Hopkins & Pillon, is described to accommodate them, and the combinationsJaffrea xerocarpa (Baill.) H. C. Hopkins & Pillon andJaffrea erubescens (Baill.) H. C. Hopkins & Pillon are published. Members of this new genus have a conical hypanthium, petals somewhat incurved at anthesis, a thick disc that is either ± lumpy or annular but not or only partly covering the semi-inferior ovary, and fruits that are ovoid-ellipsoid, strongly beaked and tardily dehiscent. As inEmmenosperma and most species ofAlphitonia, the seeds inJaffrea can remain attached to the base of the fruit after most of the pericarp has fallen.Alphitonia is now represented in New Caledonia by a single species, A. neocaledonica, and its nomenclature and types are reviewed. The generic description ofAlphitonia is amended to include the unique fruits of the New Guinean endemicA. macrocarpa, which are much larger than those of its congeners, strongly beaked, lacking a mealy endocarp, and with seeds that fall before the persistent valves. Relationships withinEmmenosperma s.l., especially the affinities ofE. papuanum andE. micropetalum, require further investigation.