The New Caledonian biodiversity hotspot contains many micro-hotspots that exhibit high plant micro- endemism, and that are facing different types and intensities of threats. The Belep archipelago, and especially Île Art, with 24 and 21 respective narrowly endemic species (1 Extinct, 21 Critically Endangered and 2 Endangered), should be considered as the most sensitive micro-hotspot of plant diversity in New Caledonia because of the high anthropogenic threat of fire. Nano-hotspots could also be defined for the low forest remnants of the southern and northern plateaus of Île Art. With an average rate of more than one new species described for New Caledonia each month since January 2000 and five new endemics for the Belep archipelago since 2009, the state of knowledge of the flora is steadily improving. The present account of eight new species from Île Art (Bocquillonia montrouzieri Gâteblé & McPherson, Cleidion artense Gâteblé & McPherson, Endiandra artensis Munzinger & McPherson, Eugenia belepiana J.W.Dawson ex N.Snow, Eugenia insulartensis J.W.Dawson ex N.Snow, Macaranga latebrosa Gâteblé & McPherson, Planchonella serpentinicola Swenson & Munzinger and Psychotria neodouarrei Barrabé & A.Martini) further demonstrates the need both to recognise the Belep Islands as a major New Caledonian micro-hotspot and to formulate concrete conservation programs for the archipelago. 

The genus Pycnandra Benth. (Sapotaceae, Chrysophylloideae) is endemic to New Caledonia with 66 known species and is subdivided in six subgenera. We have earlier revised four of these subgenera and here continue with P. subgenus Leptostylis and describe P. subgenus Wagapensia. Subgenus Leptostylis is distinguished mainly by its opposite leaves and four sepals, and includes eight species, of which two are described as new (P. amplexicaulis and P. sclerophylla). Two species, P. longiflora and P. micrantha, are assumed extinct because extensive fieldwork has not been able to relocate the plants. Variation in leaf morphology was observed in Leptostylis gatopensis, which is by consequence considered as synonym of Pycnandra filipes. Two additional taxa belong to this subgenus, but cannot presently be described because sufficient fertile material is unavailable. Subgenus Wagapensia is monotypic and readily distinguished on the basis of its subverticillate leaves and leafy shoots usually borne beneath apical clusters of leaves, a character common in Sapotaceae but unique in Pycnandra. The members of P. subgenus Leptostylis occur mainly in maquis vegetation or sclerophyllous forests on ultramafic soil, but three taxa are confined to calcareous areas. Mining activities in New Caledonian ultramafic areas are extensive and because some of these species are naturally rare, IUCN Red List assessments are provided to all species. Pycnandra grandifolia and P. wagapensis are assigned the IUCN status Vulnerable, P. amplexicaulis and P. sclerophylla are considered Endangered, P. filipes subspecies multiflora and P. goroensis are considered to be Critically Endangered, whereas P. micrantha and P. longiflora appear to be extinct.

Biogeography of Sideroxylon (Sapotoideae) and whether the satellite genera Argania and Spiniluma merit recognition are revisited. The hypothesis of an African origin with a subsequent migration to Central America via Europe and the North Atlantic landbridge is challenged. We analysed 58 accessions of trnH-psbA and ITS sequences in a fossil- calibrated, relaxed lognormal clock model with BEAST for phylogenetic and biogeographic inference. Argania spinosa (L.) Skeels from Morocco must be united with Sideroxylon, whereas S. discolor Radcl.-Sm. and S. oxyacanthum Baill. belong to subfamily Chrysophylloideae and may be recognised as Spiniluma. The divergence time estimate suggests that Sideroxylon originated and first diversified in Central America 56.3–52.2 million years ago, contemporaneous with the landbridge, but an archipelago of islands and the Tethys Seaway halted eastward expansion to Africa until c. 20 million years ago, i.e. 25 million years after establishment in Africa. Range expansion of Sideroxylon was therefore not powered by the landbridge, and a long-distance dispersal from Central America to Africa is proposed. The establishment of the Gomphotherium landbridge between Africa and Eurasia at 19 million years ago provided a land-migration route to Europe and Asia, which is reconcilable with the extension of Xantolis into Asia. Sideroxylon has colonised Socotra by over-water dispersal in the Gulf of Aden, Macaronesia, Madagascar and the Mascarene Islands.

Pycnandra Benth. (Sapotaceae) is the largest endemic genus in New Caledonia and is subdivided into six subgenera. An addition of five species are here described in four subgenera, viz. P. comptonioides Swenson & Munzinger, P. kouakouensis Swenson & Munzinger, P. montana Swenson & Munzinger, P. poindimiensis Swenson & Munzinger and P. versicolor Swenson & Munzinger. Another seven to nine taxa are discussed but remain undescribed owing to the lack of adequate collections (and may remain undescribed pending the interpretation of the Nagoya Protocol). Pycnandra is characterised by a non-areolate higher leaf venation, sepals glabrous on the inner surface, no staminodes, and a single-seeded fruit. The members occur in a wide range of habitats and most species have very specific substrate requirements, growing on ultramafic, non-ultramafic or calcareous substrates. Almost 40 species are restricted to ultramafic substrates and many are now at risk of extinction because of deforestation, deliberately set fires and mining. We provide a systematic synopsis with keys to subgenera and species, phenology, substrate preferences, altitudinal ranges and preliminary IUCN Red List assessments for all described taxa. Four of the five new species are assessed as Critically Endangered. Pycnandra versicolor is in urgent need of conservation management beacuse its entire distribution is inside an active mine on the Koniambo massif.

Pycnandra Benth., a member of subfamily Chrysophylloideae (Sapotaceae), is the largest endemic genus in New Caledonia and is subdivided into six subgenera. It circumscribes 59 species, plus an additional three described here, and nine additional species that remain undescribed for various reasons. We here use nrDNA data of ETS, ITS, and RPB2, analyse it within a Bayesian framework using BEAST, and place the new species in their respective subgenera. Pycnandra perplexaSwenson & Gâteblé is placed in subgenus Achradotypus and given a preliminary IUCN Red List assessment of Near Threatened (NT). It is confined to the ultramafic massif of southern Grande Terre and separated from the similar species P. griseosepala Vink, which is confined to non-ultramafic mountains north of the large southern ultramafic plateau. Pycnandra kopetoensis Munzinger & Swenson and P. margueriteae Munzinger & Swenson are two new micro-endemic species known only from their type localities, where habitats have been destroyed by deforestation, deliberate fires and mining activities. Pycnandra kopetoensis is named after Mount Kopéto, placed in subgenus Leptostylis, and given a preliminary assessment as Critically Endangered (CR). Pycnandra margueriteae is from a small remnant forest near Bourail and categorised as Critically Endangered (CR). Revised identification keys for subgenus Achradotypus, Leptostylis and Pycnandra are provided.

Pleioluma (Baill.) Baehni (Sapotaceae) circumscribes some 40 medium-sized trees and shrubs, many gynodioecious, in Australia, Malesia and New Caledonia. Systematics of the group is unclear and delimitations of species are notoriously difficult. We explore species boundaries in New Caledonia by multiple accessions of ‘species’, molecules and morphology in a Bayesian framework. The molecular phylogenetic signal is weak, but morphology provides enough information to support groups, species and recognition of one cryptic species. Pleioluma is then revised for New Caledonia, a genus distinguished by areolate higher leaf venation, sepals being pubescent on both surfaces, stamens inserted in or below the middle of the corolla tube, presence of staminodes, foliaceous cotyledons and endosperm. Seventeen endemic species are recognised with descriptions, recognition notes, distributions, etymologies and conservation assessments. Six species are described as new, of which four are assigned IUCN preliminary status as Critically Endangered and in urgent need of protection (Pleioluma acutifolia Swenson & Munzinger, P. belepensis Swenson & Munzinger, P. butinii Swenson & Munzinger and P. tchingouensis Swenson & Munzinger). The new species, P. dioica Swenson & Munzinger and P. tenuipedicellata Swenson & Munzinger are respectively assessed as Data Deficient and Vulnerable. The micro-endemic species P. vieillardii (Baill.) Swenson & Munzinger, confined to the Koniambo massif, is also critically endangered and needs urgent conservation management.