An Unusual Night-Flowering <I>Oxalis</I> from South Africa (Oxalidaceae)

Abstract

A new Oxalis (Oxalidaceae) species from the Hantamsberg (South Africa) is described and typified as Oxalis noctiflora using morphological, palynological, and molecular characters. Superficially it closely resembles Oxalis aridicola, Oxalis callosa, Oxalis odorata, and Oxalis primuloides, and it shares a unique supra-areolate pollen type with most of these species. No single vegetative morphological character defines this species, but a unique combination of bulb and leaflet characters distinguishes it from all other known species. The flowers of Oxalis noctiflora are unique for the genus in displaying typical moth-pollination characters. The white flowers open at night, have a long, unusually narrow, corolla tube, and produce a strong sweet scent. All previously described Oxalis species have flowers that open during the day. Phylogenetic analyses based on nuclear Internal Transcribed Spacer data placed this species sister to O. aridicola within a clade of morphologically and palynologically similar taxa.

New relatives of <I>Oxalis pes-caprae</I> (<I>Oxalidaceae</I>) from South Africa

“…Both taxa flowered ± two months after collection and these were used for morphological evaluations. Morphological characters of the two putative new taxa were studied with the aid of a Leica ES2 stereo microscope and compared to all known species of the O. pes-caprae clade (Salter 1944, 2014 and to material of unidentified Oxalis specimens housed in the NBG and BOL herbaria.…”

“…Increased collecting effort and the use of molecular identification tools has led to the discovery and description of new South African Oxalis species at an increasing rate over the past few decades (Oliver 1993, Williamson 1999, Manning & Goldblatt 2008, 2014, Suda et al 2013. The use of molecular techniques for determining phylogenetic relationships in Oxalis is especially useful, as many species are morphologically extremely variable, which often leads to misidentifications.…”