VESSELS IN ERIOCAULACEAE

The occurrence and level of specialization of vessels in 70 species re presenting 12 genera of Eriocaulaceae are presented. In all species of Eriocaulaceae and in all parts of the plant examined, vessels with si mple perforations have been identified. Correlations between level of specialization of vessel members and ecological conditions are reporte d for species from diverse habitats and species with distinct differen ces in habit. The pattern of origin and specialization of tracheary ce lls in Eriocaulaceae was compared to tracheary data for Xyridaceae, Ra pateaceae, Restionaceae and Centrolepidaceae. The evolutionary positio n of these families has been regarded as close to Eriocaulaceae.