A phylogenetically based sectional classification of Swartzia (Leguminosae‐Papilionoideae)

Abstract

The species‐rich neotropical tree genus Swartzia (Leguminosae‐Papilionoideae) is a ubiquitous element in Central and South American rainforests. As such, it has been selected as a focal group in ongoing studies of the evolution and assembly of the neotropical flora, but these efforts are hindered by substantial taxonomic problems within Swartzia. The lack of a well‐substantiated infrageneric classification has impeded much needed revisionary work on the genus, since the composition and limits of the various species complexes of Swartzia have not been clearly defined. A recent phylogenetic study of Swartzia with broad sampling of molecular characters and species illustrates the deficiencies of previous classifications of the genus and provides a robust phylogenetic framework for devising a new classification. Here we propose a phylogenetically based classification that places all currently recognized species of Swartzia into 15 sections. The sections, ranging in size from one to thirty‐two species, are morphologically diagnosable and are hypothesized to be monophyletic. Thirteen sectional names are either entirely new or are applied at the sectional rank for the first time. A key to the sections is provided, along with sectional treatments that each include a morphological description, geographic distribution, and list of included species.

Elucidating the unusual floral features ofSwartzia dipetala(Fabaceae)

“…It is closely related to the much smaller Neotropical genera Bocoa Aubl. and Candolleodendron R.S.Cowan, belonging to a ‘core swartzioid’ clade (Torke & Mansano, ). In the context of subfamily Papilionoideae, the flowers of Swartzia spp.…”

“…comm. )], a ring meristem (Tucker, 2003a; Torke & Mansano, ) and a polyandrous androecium formed by dimorphic stamens (Tucker, 2003a; Torke & Mansano, ). Most Swartzia spp.…”

Miscellaneous additions to Swartzia (Fabaceae) from Chocoan and Andean Colombia

“…In the context of the current sectional classification of Swartzia (Torke & Mansano, 2009), the new species is referable to S. section Pittierianae, characterized by the combination of spirally arranged flowers, ebracteolate pedicels, a yellow petal, an essentially glabrous gynoecium, typically with a relatively compact ovary and single-or few-seeded fruits (see also, Cowan, 1968;Torke & Schaal, 2008;Torke & Perez, 2013). The nearly actinomorphic androecium and relatively few smaller stamens and ovules suggest a fairly close relationship with the consectional species S. jorori and S. juruana, but the new species differs from (Table II).…”

“…Swartzia amabale possesses the diagnostic characters of S. sect. Unifoliolatae, including relatively few-flowered axillary inflorescences, ebracteolate pedicels, a white petal, single-seeded, ellipsoid fruits, and a unicarpellate gynoecium, with the stipe roughly twice as long as the ovary proper, the style nearly half the length of the ovary, the ovary D-shaped in outline, and the style oblique and nearly half as long as the ovary (Torke & Mansano, 2009). …”

“…We conclude that Swartzia is represented in the combined area of Caribbean, Chocoan, and Andean Colombia by some 30 species, nearly half of which are new to science. Here, we provide descriptions of three newly discovered species belonging to three disparate sections of Torke and Mansano's (2009;see also, Torke & Schaal, 2008) infrageneric classification of the genus: S. sect. Digynae Torke & Mansano, S. sect.…”