Title: A morphometric analysis and taxonomic study of Panax bipinnatifidus Seem. (Araliaceae) species complex from Sikkim Himalaya, India
KeyWords: Taxonomy, Phenetic analysis, Panaxbipinnatifidus, Sympatric distribution, Sikkim Himalaya
Year of Publication: 2020
ISSN No: NA
Author Name: Shiva K. Sharma, Maharaj K. Pandit
Details:
Abstract: The taxonomic position of Panax bipinnatifidus is controversial and problematic. To infer inter- or intra-specific morphological relationship in Panax bipinnatifidus and its allies— P. sikkimensis and P. sokpayensis, we carried out a phenetic study of these taxa, based on thirteen morphological characters (eight quantitative and fivequalitative), using univariate and multivariate analysis.The results obtained from the principle component analy-sis (PCA) and cluster analysis (CA) revealed lack oftaxonomic differences between Panax bipinnatifidus and P. sikkimensis,whereas P. sokpayensis showed distinctmorphological features. Discriminant analysis (DA) of the quantitative morphological characters also did not reveal any dissimilarity between Panax bipinnatifidus and P. sikkimensis. There were no differences between majorityof the morphological characters of Panax bipinnatifidus and P. sikkimensis except for the presence of pinnate leaflets and absence of bracts in the latter. The lack of differences in morphological characters of Panax bipinnatifidus and P. sikkimensis suggest that these two taxa are part of the same species complex. Our field studies show that Panax binnatifidus does not occur as an independent species anywhere in nature, but always shows a congeneric association with P. sikkimensis. In addition, the morphotype of undivided leaflets (P. sikkimensis) is more normal and common than the morphotype of pinnate or bipinnate leaflets (P. bipinnatifidus) in natural populations. Following the principle of priority of the International Code of Botanical Nomenclature we conclude that Panax bipinnatifidus is a distinct species, while P. sikkimensis is a synonym of P. bipinnatifidus in Indian Himalaya. Based on thepresent investigations we propose that Panax bipinnatifidusSeem. should be given recognition and priority for thespecific rank as opposed to the views of earlier workers. A taxonomic key of the studied taxa is provided.