New Lepidium (Brassicaceae) from New Zealand

A revision of the New Zealand endemic Lepidium oleraceum and allied species is presented. Sixteen species are recognised, 10 of these are new. The new species are segregated on the basis of morphological characters supported by molecular data obtained from three DNA markers (two rDNA and one cpDNA). One species, L. castellanum sp. nov., is endemic to the Kermadec Islands where it is sympatric with L. oleraceum. The North Island of New Zealand supports four species, with two of them, L. amissum sp. nov. and L. obtusatum, now extinct. The South Island supports six species, that, aside from L. banksii, L. flexicaule and L. oleraceum, are all confined to the south-eastern half of the island (L. aegrum sp. nov., L. crassum sp. nov. and L. juvencum sp. nov.). One of these, L. juvencum sp. nov., extends to Stewart Island. The Chatham Islands support six species (L. flexicaule, L. oblitum sp. nov., L. oleraceum, L. oligodontum sp. nov., L. panniforme sp. nov., and L. rekohuense sp. nov.), one of which, L. oligodontum sp. nov., extends to the Antipodes Islands group. The remote, subantarctic Bounty Islands group supports one endemic, L. seditiosum sp. nov., which is the only vascular plant to be recorded from there. Lepidium limenophylax sp. nov. is known from islands off the south-western side of Stewart Island/Rakiura, The Snares and Auckland islands. Lepidium naufragorum, although not related to L. oleraceum and its allies, is also treated because populations with entire leaves are now known. Typification is undertaken for L. banksii, L. oleraceum, L. oleraceum var. acutidentatum, var. frondosum and var. serrulatum.