The identity of Bupleurumjeholense (Apiaceae)

Area of Science:

• Botany
• Plant Taxonomy
• Molecular Phylogenetics

Background:

• Bupleurumjeholense Nakai, native to China, was initially described as a species, then as a variety of B.sibiricum.
• Recent findings suggest a closer relationship between B.jeholense and B.chinense, necessitating a taxonomic re-evaluation.

Purpose of the Study:

• To determine the precise taxonomic status of B.sibiricum var. jeholense.
• To clarify the phylogenetic position of B.jeholense within the Bupleurum genus.

Main Methods:

• Morphological analysis comparing key floral and vegetative characteristics.
• Chromosome counting to establish ploidy levels and karyotype.
• Phylogenetic analysis using complete chloroplast genome data.

Main Results:

• B.sibiricum var. jeholense shares diagnostic features (e.g., 5 bracteoles, solid stem) with B.chinense, differentiating them from B.sibiricum var. sibiricum.
• Chromosome number for B.sibiricum var. jeholense is 2n=12, matching B.chinense, while B.sibiricum var. sibiricum has 2n=64.
• Phylogenetic analysis strongly supports the close relationship between B.sibiricum var. jeholense and B.chinense.

Conclusions:

• Morphological, chromosomal, and genomic data support the reclassification of B.sibiricum var. jeholense.
• A new combination, Bupleurumchinense var. jeholense (Nakai) Q.R.Liu & L.H.Wang, is proposed based on the evidence.
• The primary distinctions between the new variety and B.chinense lie in plant height, stem number, and middle stem leaf characteristics.