Septal nectary anatomy and phylogeny of the Haemodoraceae

Septal nectary anatomy of members of the Haemodoraceae is described, with emphasis on nectary number and relative position within the ovary. Three types of septal nectaries are defined: infralocular, interlocular, and supralocular. The phylogenetic and possible adaptive significance of these features are assessed by adding the data to a previous cladistic analysis of the Haemodoraceae and considering cladistic patterns in terms of functional floral morphology. I hypothesize that: 1) three interlocular septal nectaries are ancestral for the Haemodoraceae, but were secondarily acquired in the genus Anigozanthos (Conostylideae) in response to selective pressure for increased nectar production for bird pollination; 2) three supralocular nectaries constitute a synapomorphy for all or most of the tribe Conostylideae, but evolved independently in the genus Dilatris of the Haemodoreae; 3) two infralocular nectaries evolved concomitantly with unique "perianth apertures" and arose via the evolution of zygomorphy and basal displacement of nectaries into the receptacular tissue; and 4) septal nectaries were independently lost in the genera Xiphidium and Phlebocarya, perhaps in response to a shift in pollination mechanism