Phylogeny of Chamaecrista Moench (Leguminosae­Caesalpinioideae) based on nuclear and chloroplast DNA regions

Abstract

Chamaecrista Moench is a genus of caesalpinioid legumes with about 330 species mostly from the New World. The phylogeny of the genus was studied using sequence data from nuclear ITS and plastid trnL­F DNA spacers, representing all six sections of Chamaecrista. Separate and combined analyses recovered the same major clades with high bootstrap and posterior probabilities support, except for the subclades of representatives of sections Caliciopsis, Chamaecrista, and Xerocalyx. The monophyly of Chamaecrista was highly supported in all analyses. Sections Apoucouita and Xerocalyx were supported as monophyletic, sect. Absus was paraphyletic and subsect. Baseophyllum was resolved more closely related to species of sections Chamaecrista, Caliciopsis, and Xerocalyx than to subsect. Absus. The monotypic section Grimaldia was embedded within subsect. Absus. Section Chamaecrista was paraphyletic with respect to sections Caliciopsis and Xerocalyx. Our analyses suggest that the diversification patterns in Chamaecrista occurred through an initial shift from rainforest trees to a more diverse clade of savannah shrubs. Within the latter group, two main subclades were recovered: (1) a planaltine and high­mountain clade characterized by absence of extrafloral nectaries and the appearance of sticky glandular hairs; and (2) a mostly herbaceous clade with axillary fascicled inflorescences and reduced chromosome numbers. This last group is more diverse in open grassland areas and includes many colonizers of waste ground.

Extrafloral nectaries in Leguminosae: phylogenetic distribution, morphological diversity and evolution

“…[Note: Lersten and Curtis (1996, p. 29 On the petiole and along the rachis between leaflets; stalked or sessile. Irwin and Barneby (1982); de Souza Conceição et al (2009); Melo et al (2010aMelo et al ( , 2010b; Coutinho et al (2012); Coutinho and Meira (2015); Silva et al (2017); Gonzalez and Marazzi (2018); this study Barneby (1982); Marazzi et al (2006), Marazzi and Sanderson (2010); Marazzi et al (2013b); Gonzalez and Marazzi (2018); this study…”

Phylogenetic relationships within Chamaecrista sect. Xerocalyx (Leguminosae, Caesalpinioideae) inferred from the cpDNA trnE-trnT intergenic spacer and nrDNA ITS sequences

“…Chamaecrista as suggested by de Souza Conceição et al (2009). None of the trees analyzed showed the microphyllous and the macrophyllous groups as distinct clades.…”

“…There is also disagreement about sister-group relationships in Cassiinae. One hypothesis considers Chamaecrista a clade distinct from its sister taxa Senna and Cassia ( Bruneau et al , 2001 , 2008 ; Marazzi et al , 2006 ; de Souza Conceição et al , 2009 ). However, other studies ( Doyle et al , 1997 ; Kajita et al , 2001 ; Herendeen et al , 2003 ) indicate that Senna and Chamaecrista are sister taxa and that Cassia occurs in a distinct clade.…”

Simultaneous pulsed flowering in a temperate legume: causes and consequences of multimodality in the shape of floral display schedules

“…Chamaecrista is of tropical descent, perhaps evolving from a rain forest tree to a savanna shrub prior to its colonization of temperate zones (de Souza Conceição et al . ). Multimodality in display schedules is more common in the tropics (Newstrom, Frankie & Baker ), and the unique pattern of flowering found in C. fasciculata may be explained by its tropical origin.…”