Studies on Collaea species (Fabaceae) occurring in Brazil: taxonomic novelties, new interpretations about the leaf of the genus, and new leaf anatomical characters for American Fabaceae

Collaea insignis, a new species from Midwestern of Brazil, is described and illustrated from plants recognized as C. speciosa or misinterpreted as C. aschersoniana and C. stenophylla. However, the association of the morphological (e.g., morphology of leaves, flowers and indument types), leaf anatomical (see below), and geographical (allopatric distribution) features led us to recognized such species, and also propose four lectotypes and a synonym within this Collaea group. The leaf anatomy of Collaea species is described here for the first time, and it is noteworthy that all species present stomata in crypts, a rare feature in plants, and not described in the American Fabaceae. Other characters such as indumented leaflets, thick cuticle, palisade parenchyma with 2 or 3 layers of cells, spongy parenchyma with 1–3 layers of loosened cells, cortex in the midrib, petiole, pulvinus and pulvinules with rhombohedral crystals, bicollateral vascular bundles in the midrib and collateral in the petiole and petiole, and common epidermal cells with different shapes and sizes between the abaxial, and adaxial surfaces are also provided for the first time for the genus. In addition to several vegetative and reproductive characters that can be used to separate the new species from morphologically similar congeners. The studied species can be anatomically differentiated by a set of characters such as contour of the midrib, pulvinus, and puvinules, presence or absence of petiole, type of the vascular bundles of the mesophyll, midrib, and pulvinules, type of sheath extension surrounding the vascular bundles in the mesophyll and its direction, as well as the number of parenchyma and collenchyma layers in the cortex of the midrib, pulvinus and pulvinules. In addition to the taxonomic, and macro and micromorphological novelties, new interpretations about the leaf of the genus are proposed.