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Rhizophora mangle L., one of the most common mangrove species, has an aerial structure system that gives it stability in permanently swampy soils. In fact, these structures, known as "aerial roots" or "stilt roots", have proven to be peculiar branches with positive geotropism, which form a large number of roots when in contact with swampy soils. These organs have a sympodial branching system, wide pith, slightly thickened cortex, collateral vascular bundles, polyarch stele and endarch protoxylem, as in the stem, and a periderm produced by a phellogen at the apex similar to a root cap. They also have the same type of trichosclereid that occurs in the stem, with negative geotropism, unlike true Rhizophora roots, which do not form trichosclereids at all. On the other hand, these branches do not form leaves and in this respect they are similar to roots. These peculiar branches are rhizophores or special root-bearing branches, analogous to those found in Lepidodendrales and other Carboniferous tree ferns that grew in swampy soils.

Morpho-anatomical studies of fruits are scarce in monocotyledons and particularly for the Brazilian species of Velloziaceae, a small family of monocots characteristic of the campo rupestre vegetation of Brazil. The main fruit types found in Velloziaceae are poricidal and loculicidal capsules, but capsule morphology is variable, which has led to discrepancies regarding fruit descriptions and terminology. In this study, we aimed to analyse fruit development in Brazilian Velloziaceae to obtain a better understanding of capsule dehiscence and to elucidate and describe in detail the fruit types occurring in the family. Based on our results, we discuss the terminology used to describe capsules of some species, e.g. capsules of Vellozia minima and V. epidendroides , previously classified as poricidal, should be called apical loculicidal, as they form three slits on the uppermost part of each carpel that are prevented from extending downwards by the precocious lignification of the pericarp. Capsules of Barbacenia purpurea , B. riparia and B. plantaginea have been classified using various terms, but they fit the definition of fissuricidal capsule and should be classified as such. We also propose an improved analysis for the character 'fruit type', previously used in phylogenetic reconstructions of Velloziaceae. We changed some states following the fruit reclassification proposed here and added a new state, 'capsule opening through lateral irregular aperture', to the character. Additionally, eight new phylogenetic characters derived from ovary and fruit characteristics are suggested. [ABSTRACT FROM AUTHOR]