Root character evolution and systematics in Cranichidinae, Prescottiinae and Spiranthinae (Orchidaceae, Cranichideae).

Background And Aims: Previous studies have suggested that velamen characteristics are useful as taxonomic markers in Orchidaceae. Members of tribe Cranichideae have been assigned to two velamen types constructed based on combinations of characters such as the presence of secondary cell-wall thickenings and pores. However, such characters have not been analysed on an individual basis in explicit cladistic analyses.