FLORAL ANATOMY AND SYSTEMATIC POSITION OF DIPLARRHENA (IRIDACEAE): A NEW TRIBE DIPLARRHENEAE

Abstract

This paper describes floral anatomy and pollen morphology in Diplarrhena latifolia in relation to the systematic position of the genus, which is taxonomically isolated and unique in Iridaceae in having only two stamens. Although the loss of a stamen is autapomorphic for Diplarrhena, some characters, especially presence of septal nectaries and pollen sculpturing, indicate an association with Nivenioideae. However, since Diplarrhena lacks the main synapomorphy for Nivenioideae: inflorescences in binate rhipidia, and also lacks the repeated codon of the rps4 gene found in the Nivenioid-Ixioid clade, its subfamilial classification is problematic, and a new monogeneric tribe Diplarrheneae is proposed.