Anatomy of the vegetative organs, inflorescence axis and pedicel in the Neoregelia bahiana complex (Bromeliaceae): taxonomic and ecological importance

Delimitation of Bromeliaceae into genera or species is often problematic, as observed for the Neoregelia bahiana complex, distributed throughout the rocky fields of Espinhaço Range, Brazil. Considering that the anatomical characterisation of different organs is potentially important for taxonomic and ecological interpretation of this complex, we analysed roots, stems (stolon), leaves, inflorescence axes (peduncle), and pedicels in individuals from different populations. In all the studied individuals, the roots are composed of velamen, a heterogeneous cortex, and a polyarch vascular cylinder with sclerenchymatous pith. The stolon features a parenchymatous cortex and collateral vascular bundles randomly distributed in the vascular cylinder. This organ may increase in diameter by the formation of new vascular bundles and a multi-layered cork. The leaf blade has epidermal cells with U-shaped thickened walls and peltate scales occur on the adaxial surface. The mesophyll consists of mechanic...