Rinorea niccolifera (Violaceae), a new, nickel-hyperaccumulating species from Luzon Island, Philippines

A new, nickel-hyperaccumulating species of Rinorea (Violaceae), Rinorea niccolifera Fernando, from Luzon Island, Philippines, is described and illustrated. This species is most similar to the widespread Rinorea bengalensis by its fasciculate inflorescences and smooth subglobose fruits with 3 seeds, but it differs by its glabrous ovary with shorter style (5 mm long), the summit of the staminal tube sinuate to entire and the outer surface smooth, generally smaller leaves (3-8 cm long × 2-3 cm wide), and smaller fruits (0.6-0.8 cm diameter). Rinorea niccolifera accumulates to >18,000 µg g(-1) of nickel in its leaf tissues and is thus regarded as a Ni hyperaccumulator.