Floral micromorphological, palynological, and carpological characteristics of the rare endemic Korean species Peucedanum miroense (Apiaceae)

Peucedanum miroense K. Kim, H.-J. Suh & J.-H. Song, recently reported as a new species endemic to South Korea, is distributed on mountains Duta-san and Swinum-san in Gangwon Province, South Korea. Given its conspicuously limited habitat range and small populations, this species qualifies as an endangered Red List species. In this study, we undertook a detailed investigation of the floral micromorphological, palynological, and carpological characters of P. miroense based on a range of microscopic analyses. Examination of the floral micromorphology of P. miroense revealed that the surface patterns of bractlets have potential utility in taxonomy studies of the genus Peucedanum. In addition, we established that this plant is characterized a papillose conical-tabular rugose pattern of petal epidermal cells and bears sunken nectary slits on the stylopodium. Also identified were simple spherical orbicules bearing psilate surface ornamentation, as well as small tricolporate prolate to perprolate pollen grains characterized by verrucate and gemmate ornamentation. Moreover, we verified pollen wall stratification and presence of pollenkitt. The mericarps had colliculate-striate surface patterns with trichomes and eight or nine vittae, and prismatic crystals were detected in different layers of the pericarp. We believe that the findings of this study will contribute to an evaluation of the taxonomic significance of this species within the genus Peucedanum, and also provide valuable information for the conservation of this rare endemic species.

Automated summary

This study conducted a detailed investigation on the floral micromorphology, palynology, and carpology of the endemic species Peucedanum miroense in South Korea. The findings provide valuable information for the taxonomic evaluation and conservation of this rare species.