Systematic reinstatement of highly sacred Ficus krishnae based on differences in morphology and DNA barcoding from Ficus benghalensis (Moraceae)

Ficus krishnae is considered as native to India and is well-known for the peculiarity in nature of its cup-shaped leaves where both the vernacular name (Krishna Fig) and specific epithet were derived. The taxonomic status of Ficus krishnae is still unclear and currently treated as a subspecies or variety under Ficus benghalensis. In the present study, morphological characters and molecular analysis were employed to address their species delimitation. The spacer markers ITS2 and trnH-psbA were used for constructing phylogenetic trees along with morphometric analysis. Ficus krishnae distinctly differs from Ficus benghalensis by having cup-forming leaves and the nature of the aerial roots, stipules, petioles, ostiolar bracts of the receptacle, DNA content, chromosome differences and nodal anatomy. The results showed that the highest divergence is observed in trnH-psbA (20.8 ± 12.2), followed by ITS2 (5.7 ± 3.2). The phylogenetic tree construction using Bayesian analysis showed a divergent boundary between the two species suggesting that F. krishnae could be an independent species, not a variety of F. benghalensis. The present study’s findings support the view that these two floras can be treated as different species.

Conflict between morphological and molecular data: A case study of Ficus krishnae (Moraceae)

Ficus krishnae, considered as highly sacred plant species in India, is well known for its peculiar nature of cup-shaped leaves. The species distinctly differs from its allied species F. benghalensis not only in the cup formation in leaves but also in the height of plants, aerial roots, stipules, petiole and its leafy appendages, ostiolar bracts of the receptacle and pollinator wasps, in addition to slight differences in the karyotype, DNA contents, stomatal and parenchymatous cells and nodal anatomy. In spite of having several morphological differences, F. krishnae is considered by some authors as a synonym of F. benghalensis, which does not seem to be convincing. Contrary to the morphological differences, the sequence analysis of nuclear and plastid regions of both the species conducted in the present study does not reveal any significant variations and thus infers no differentiation between the species at molecular level. This may be due to mutations at one or few coding loci or differences in gene expression associated with morphogenesis with significant phenotypic appearance.

Revisit the taxonomy of Ficus krishnae (Moraceae)

Ficus krishnae considered as native to India is very unique among all species in the genus as it has peculiar leaves generally with cone-shaped structure at base and leaflet like appendages on the petiole. These both features are tremendously variable within the species. The taxonomic status of F. krishnae is still uncertain as sometimes it is treated as subspecies or conspecific to its closest relative F. benghalensis. Many mythological stories regarding the formation of cup in the leaves are also associated in India and hence the plants of the species are considered sacred and worshiped. The merger of F. krishnae with F. benghalensis makes the latter quite heterogeneous and at the same time it may not be acceptable in the society at large as with the former the religious faith of the people is attached. Earlier it was believed that F. krishnae differs from F. benghalensis only in cup-shaped leaves. But critical examination of large number of specimens gathered from different places and available information reveal that F. krishnae distinctly differs from F. benghalensis not only in cup formation in leaves, rather also in height of the plants, aerial roots, stipules, petiole and its leafy appendages and ostiolar bracts of the receptacle, in addition to differences in chromosome, DNA contents, stomatal and parenchymatous cells and nodal anatomy. Based on morphological, anatomical and cytological evidences F. krishnae is again reinstated here as a correct species. The correct citation of the species has been provided and discussion has been made on the variation pattern of the leaves. The detail description of the species along with line drawing illustrations and colour photographs has been added.