A revised circumscription of the species in Bracteatae complex (section Calycinae) in the genus Crotalaria L.: evidence from nuclear and chloroplast markers

Abstract

The existing sectional classification of the genus Crotalaria has merged the Indian sections Calycinae and Crotalaria under the section Calycinae Wight & Arn. emend. M.M.Le Roux & B.-E.van Wyk.Crotalaria subsection Bracteatae is re-evaluated to ascertain its position in the Calycinae clade. Evidences from morphological and molecular sequence data (ITS and trnL-F regions) are used to assess the subsectional position of Bracteatae. Within the recognized 12 species in the subsection, the morphological characters currently used to distinguish these species, are insignificant and overlapping and do not merit diagnostic characters of the species. Examination of the types and vouchers at different herbaria and specimens collected during field trips enabled us for a new interpretation of the existing circumscription of the species. Further, pod anatomical and molecular sequence data were also used for the delimitation of the species. Based on the results of the above studies, a new circumscription has been formalized here and contains five recognized species in the Bracteatae clade, viz., C. berteroana DC., C. longipes Wight & Arn., C. paniculata Willd., C. pulchra DC. and C. pellita DC. of the section Calycinae emend. M.M.Le Roux & B.-E.van Wyk. Crotalaria subsection Bracteatae appeared to be a well supported monophyletic group, but nested within the Calycinae clade. In order to maintain the monophyly of Crotalaria section Calycinae, Bracteatae is synonymized with the former.

Discovery of two new species of Crotalaria (Leguminosae, Crotalarieae) from Western Ghats, India

“…Of these 33 species collected, 40% are endemic. A total of 94 accessions for the ITS marker and 86 for the plastid marker matK (including outgroups) of which 72 accessions represent Indian species of Crotalaria [ 8 , 15 ]. Bolusia amboensis (Schinz) Harms and Euchlora hirsuta (Thunb.)…”

“…In Asia, India hosts the maximum number of species with radiations in Pakistan (15 species) [ 13 ] and South East Asia which includes: Indonesia, Laos, Philippines, Vietnam, Cambodia, Malaysia, Thailand, Myanmar, Brunei, Singapore, Timor-leste, Andaman and Nicobar Islands (with 105 species) [ 14 ]. In India, the genus is represented by 85 species [ 15 – 16 ], of which 73 species are restricted to Peninsular India (Karnataka, Andhra Pradesh, Kerala, and Tamil Nadu). The species are concentrated mainly in the belt of Western Ghats (the Sahyadri) starting from Maharashtra , south of the Tapti river , and running approximately 1,600 km through the states of Maharashtra , Goa , Karnataka , Kerala and Tamil Nadu ending at Kanyakumari , at the southern tip of India [ 10 – 12 , 15 ].…”

“…In India, the genus is represented by 85 species [ 15 – 16 ], of which 73 species are restricted to Peninsular India (Karnataka, Andhra Pradesh, Kerala, and Tamil Nadu). The species are concentrated mainly in the belt of Western Ghats (the Sahyadri) starting from Maharashtra , south of the Tapti river , and running approximately 1,600 km through the states of Maharashtra , Goa , Karnataka , Kerala and Tamil Nadu ending at Kanyakumari , at the southern tip of India [ 10 – 12 , 15 ]. Of the total species of Crotalaria naturally occurring in India, 47% are endemic to Peninsular India [ 16 ].…”

“…The genus is recognized by a distinctive combination of characters, rostrate keel, inflated pod, hairy style, five plus five anther configuration, paired callosities on the standard petal and the presence of pyrrolizidine alkaloids [ 6 , 15 ].…”

Clock-dated phylogeny for 48% of the 700 species of Crotalaria (Fabaceae–Papilionoideae) resolves sections worldwide and implies conserved flower and leaf traits throughout its pantropical range

“…Here we focus on Crotalaria , a pantropical clade of woody or herbaceous species of low statue that mostly occur in open habitats at low to mid-altitudes and that have conspicuous flowers and fruits so that they are frequently collected and well represented in herbaria. Understanding of Crotalaria has benefitted from consistent taxonomic work by Roger Polhill [ 48 , 49 ] and modern phylogenetic studies focusing on its African and Indian species [ 37 , 57 , 58 ]. Of the 700 species, about 500 occur in Africa and Madagascar, 80 in India, 20 in Australia, and 80 in the Americas [ 14 , 38 , 49 ].…”