Revision of Pichonia (Sapotaceae) in New Caledonia

Abstract

Pichonia Pierre (Sapotaceae, Chrysophylloideae) is a small genus of 10 species in Australasia, of which seven are endemic to New Caledonia. We revise the genus for New Caledonia and describe one new species (P. grandiflora), resurrect another (P. dubia) and make two new combinations because of nomenclatural priority (P. balansae, P. deplanchei). P. balansae has been known for decades as P. calomeris, a name that in fact has never been validly published. The members are mainly found in Grande Terre, the main island of New Caledonia, but two species extend to Belep Islands in the north and to Isle of Pines in the south of the archipelago. Most grow in maquis vegetation at low altitudes, on ultramafic soils, preferably serpentinite. The exceptions are P. balansana, confined to limestone areas, and P. dubia that is a large canopy tree of the humid forest on ultramafic soil. Pichonia is distinguished by a character combination of an areolate higher venation, staminodes, a single-seeded fruit, plano-convex cotyledons and absence of endosperm. Because of being restricted to ultramafic soils, they are subsequently sensitive to present and future mining activities in New Caledonia. Hence, preliminary IUCN Red List assessments for all members are provided. P. balansana, P. daenikeri and P. lecomtei are all naturally uncommon, do not occur in any protected area and are proposed the IUCN status of Vulnerable. The herein described species P. grandiflora is rare in nature, known only from the Boulinda–Paéoua–Kopéto Mountains, and is in urgent need of protection. It is therefore assigned a preliminary status of Endangered.