Structure of the inflorescences of selected South American species of Abildgaardia Vahl, Bulbostylis Kunth, and Fimbristylis Vahl (Abildgaardieae-Cyperoideae-Cyperaceae)

Abstract

Abildgaardieae poses several taxonomic challenges, because there is no general agreement on its circumscription and infrageneric divisions. With the objective of providing data with taxonomic and phylogenetic value, the structures of the inflorescences of Abildgaardia, Bulbostylis, and Fimbristylis were analyzed following the methodology and terminology of Troll's school. The inflorescences studied are polytelic and may comprise only the main florescence or may also show a paracladial zone below it. They are unispiculate, anthela-like, or capitate, and can be terminal, pseudolateral, or in an intermediate position. Normal and prophyllar branching patterns are observed. The acropetal reduction in the order and number of ramifications, and the length of bracts and prophylls were recorded. Foliose structures with an intermediate form between a setaceous bract and a glume are frequently found at the spikelet base. Hypotheses of the homology of these structures, and a list of inflorescence characteristics and character states are presented. The branching pattern of the inflorescence seems to be the main characteristic with potential taxonomic and phylogenetic implications at genus level. The rest of the characteristics could possibly be useful for infrageneric divisions.