Discussion
Taxonomy: The new species shares similarities with those classified under the genus Madaractis DC. Candolle (1838) initially identified four species (M. glabra DC., M. pinnatifida DC., M. polycephala DC., M. scabra DC.) in this genus. Clarke (1876) considered it as a subgenus and included a total of 17 species. Among them, S. bombayensis (Syn. S. reticulatus C.B.Clarke) was the only species included under subsectionSub-paleata of section 1 (members of peninsular India). The subsection is characterised by the presence of sub-paleaceous nature of pappus which was also observed in S. anjanericus . Other members of the section found in Maharashtra are S. belgaumensis (Wight) C.B.Clarke, S. dalzellii C.B.Clarke and S. edgeworthiiHook.f. (Syn. S. tomentosus (Wight) C.B.Clarke). These members are further characterized by lax corymbs, uniseriate involucre, ray florets epappose, cypselae of ray florets sometimes abortive, anthers ecaudate, and pappus rigid and scabrid. Hooker (1881) mentioned two more species (both occurring in Maharashtra), S. hewrensis (Dalzell) Hook.f. and S. gibsonii Hook.f. under section Madaractis .S. anjanericus falls under this section; however, none of the above-mentioned species show supplementary bracts in addition to uniseriate involucre that sets S. anjanericus apart from the other species of the group.
Cytogenetics: Cytological information for Senecio is very scarce in India, covering about 40% of the total species. Within the section Madaractis (DC.) Hook.f., four species have had their chromosome numbers identified previously: S. bombayensis (Syn.S. grahamii Hook.f.), S. hewrensis and S. wightii(DC.) Benth. ex C.B.Clarke (Syn. S. saxatilis Wall.) have a common chromosome number 2n ­=20 (Gupta and Gill 1979, Gosavi et al. 2020) while S. dalzellii with n =20 (Matthew and Matthew 1988). Additionally, the karyotypic formula for S. hewrensis is reported as 10m (Gosavi et al. 2020) and for S. wightii , it is 9m+1sm (Matthew and Matthew 1988). Based on the available information, it is observed that the species of the section have a base number x =10. S. anjanericus , with a chromosome number of 2n =20 and a karyotype formula of 10m, appears to have a close relationship with the other members of group.
Karyotype of S. bombayensis was more asymmetric than S. anjanericus . Also, bimodality was more conspicuous in S. bombayensis with the value of ratio of the longest to shortest chromosome of a complement (R) 2.46 in contrast to 1.74 in S. anjanericus . The higher values of MCA (10.43) and CVCL (31.94) in S. bombayensis indicated variation in chromosome type and heterogeneity in chromosome length of the complement. This is also reflected in the karyotype formula of the species, i.e. 9m+1sm and the range in chromosome length, 3.42 – 1.39 µm. High CVCI (12.60) in S. bombayensis than S. anjanericus (2.75) reflects the shift of centromere from median to sub-median position. Additionally, the secondary constriction inS. anjanericus was located on the short arm whereas in S. bombayensis it was on the long arm.
Conflict of interest: The authors declare that they have no conflict of interest.
Significance statement: The significance of this study lies in expanding our understanding of genus Senecio in Maharashtra and its position. The detailed morphological and cytogenetic analyses provide essential data for further research on the evolutionary relationships and ecological roles of Senecio species in the Western Ghats, emphasizing the importance of the Anjaneri Hills as a rich biodiversity hotspot.
Data archiving statement: The data associated with this study, the type and voucher specimens have been deposited in the Herbarium of Shivaji University, Kolhapur (SUK). Access to this archived data can be facilitated through appropriate channels, and researchers interested in further examination or validation of the findings can contact the corresponding author for access to the materials at SUK.