An Integrative Systematic Approach Reveals a New Species of Crocus Series Verni (Iridaceae) Endemic to Albania.

Abstract

The allopolyploid complexes in Crocus series Verni represent taxonomic challenges due to their variable or mostly overlapping morphology with one parental species. Moreover, their diploid ancestors remain unidentified, even with genome-wide SNP data. One such case, collected from the southeasternmost point of the series' geographical distribution, is herein characterised and described as a new species, C. bachofenii. This study integrates phylogenomics and cytogenetics to infer the parental origin of C. bachofenii and establish its diagnostic morphological characteristics. Genome skimming of C. bachofenii and 10 other C. ser. Verni species enabled the development of novel satellite repeats as cytogenetic markers and the assembly of their complete chloroplast genomes that were employed for phylogenetic analysis alongside GBS data. The allopolyploid origin of C. bachofenii (2n = 16) was confirmed with C. vernus as the maternal parent. The probably extinct paternal parent was affiliated with a clade comprising C. heuffelianus, C. tommasinianus, C. kosaninii, and C. bertiscensis. Morphologically, C. bachofenii is distinguished by larger flowers, perigone segment coloration, and a stigma-anther ratio from its close relatives. In conclusion, its phylogenetic affiliation, distinctive cytological status, and unique morphological features justified the description of this taxon as a new species.