Reinstatement of Ticanto (Leguminosae-Caesalpinioideae) –the final piece in the Caesalpinia group puzzle

Abstract

A recent molecular phylogenetic analysis of the Caesalpinia group demonstrated that it comprises 26 genera, but the recognition of a putative 27th genus, Ticanto, remained in doubt. This study presents a phylogenetic analysis of ITS and five plastid loci revealing a robustly supported monophyletic group representing the Ticanto clade, sister to the morphologically distinct genus Pterolobium. Based upon this evidence, along with a morphological evaluation, the genus Ticanto is here reinstated. Descriptions are provided for all nine species of Ticanto, together with a key to the species, maps, and colour photographs. Nine new combinations are made: Ticanto caesia (Hand.-Mazz.) R. Clark & Gagnon, T. crista (L.) R. Clark & Gagnon, T. elliptifolia (S. J. Li, Z. Y. Chen & D. X. Zhang) R. Clark & Gagnon, T. magnifoliolata (Metcalf) R. Clark & Gagnon, T. rhombifolia R. Clark & Gagnon, T. sinensis (Hemsl.) R. Clark & Gagnon, T. szechuenensis (Craib) R. Clark & Gagnon, T. vernalis (Champion ex Benth.) R. Clark & Gagnon and T. yunnanensis (S. J. Li, D. X. Zhang & Z.Y. Chen) R. Clark & Gagnon. The final major question in the delimitation of segregate genera from within Caesalpinia sensu lato and the Caesalpinia group is thus resolved.