Two new species of Oxalis sect. Polymorphae (Oxalidaceae) from the Brazilian Atlantic Forest

Summary: Two new species of Oxalis L. sect. Polymorphae (Oxalidaceae) are here described and illustrated. Oxalis colatinensis Fiaschi is similar to O. blackii Lourteig, from which it can be distinguished by the unbranched (vs branched) habit, leaves grouped in a single terminal whorl (vs multiple whorls), leaflet lamina with an evident (vs indistinct) reticulation, and the terminal lamina 2 - 6. 6 × 1. 7 - 3. 8 cm (vs 1 - 2 (- 3) × 0. 5 - 1. 3 cm), with a rounded to slightly cordate (vs cuneate or obtuse) base. O. kollmannii Fiaschi is similar to O. neuwiedii Zucc., from which it can be distinguished by having leaves with petioles longer than the lamina (vs shorter), leaflet lamina with the apex acute and a somewhat rounded tip (vs apex usually acuminate), and symmetrical to very slightly asymmetrical (vs markedly asymmetrical) lateral leaflets. Comments on the geographic distribution, habitat preference, etymology and conservation status of these two new species are also provided. © 2012 The Board of Trustees of the Royal Botanic Gardens, Kew.