Sucupira-branca (Pterodon - Fabaceae): does wood anatomy support the distinction among species and hybrid?

Abstract

Pterodon (Fabaceae) species known as "sucupira-branca" are traditionally used in Brazilian medicine. This South American monophyletic genus has species delimitation problems. To separate the recognized Pterodon species we described the wood anatomy of P. abruptus, P. emarginatus, P. pubescens, hybrid (between P. emarginatus and P. pubescens) and P. apparicioi, the latter two for the first time. Wood anatomical studies were undertaken, and qualitative and quantitative features statistically tested. Qualitatively the species are very similar, but in most quantitative features, differences were observed, especially axial parenchyma quantity and type. Pterodon abruptus was easily separated by high density narrow vessels allied to a low area of axial parenchyma but with confluent almost forming bands. Hybrid was more similar to P. emarginatus and had a significantly greater axial parenchyma area than other Pterodon species. PCA analysis separates only P. abruptus. Cluster analysis using qualitative and quantitative data were able to separate P. abruptus and P. apparicioi from the other species. Vessels, ray and axial parenchyma features enable to clarify the distinction in identification key.