New names and status for Pacific spiny species of Solanum (Solanaceae, subgenus Leptostemonum Bitter; the Leptostemonum Clade).

Five new species of spiny solanums (Solanum subgenus Leptostemonum Bitter; the Leptostemonum Clade) are described from the islands of the Pacific. Two of the new species are from Fiji (S. pseudopedunculatum D.McClelland, sp. nov. and S. ratale D.McClelland, sp. nov.), two from New Caledonia (S. memoayanum D.McClelland, sp. nov. and S. semisucculentum D.McClelland, sp. nov.), one from Papua New Guinea (S. labyrinthinum D.McClelland, sp. nov.) and another from Vanuatu (S. vanuatuense D.McClelland, sp. nov.). A new status and combination is provided for the rare Hawaiian endemic S. caumii (F.Br.) D.McClelland, comb. et stat. nov. and a new type designated for S. peekelii Bitter of Papua New Guinea, for which a description is also provided. All species are illustrated with digitized herbarium specimens, mapped and have been assigned a preliminary conservation status using current IUCN guidelines. Details of all specimens examined are provided in a Suppl. materials 1: file SM1.

Flowering plant immune repertoires expand under mycorrhizal symbiosis.

Immune perception in flowering plants is mediated by a repertoire of cytoplasmic and cell-surface receptors that detect invading microbes and their effects on cells. Here, we show that several large families of immune receptors exhibit size variations related to a plant's competence to host symbiotic root fungi (mycorrhiza). Plants that do not participate in mycorrhizal associations have significantly smaller immune repertoires, while the most promiscuous symbiotic hosts (ectomycorrhizal plant species) have significantly larger immune repertoires. By contrast, we find no significant increase in immune repertoire size among legumes competent to form a symbiosis with nitrogen-fixing bacteria (rhizobia). To explain these observations, we hypothesize that plant immune repertoire size expands with symbiote species diversity.