Fruit anatomy of the genus Pimpinella L. (Apiaceae) in Iran

The genus Pimpinella L., with about 170–180 species in the world, is one of the largest genera of the family Apiaceae (Umbelliferae). Based on the Flora Iranica treatment, this genus has 25 species in the Iranian plateau, including 19 species in Iran, and six of those (P. tragioides, P. deverroides, P. pastinacifolia, P. anisactis, P. khorasanica and P. khayyamii) are endemic.In this research, Iranian species of Pimpinella were anatomically studied for the first time. For this genus, some of the most taxonomically important fruit characteristics are: mericarp shape in transverse section, homomorphism of mericarps, number of lateral and marginal ribs, ratio of mericarp width (parallel to commissural side) to its length, ratio of mericarp width to its thickness, presence or absence of hypodermal collenchyma, mesocarp and endocarp lignification, number of vascular bundles, number of vallecular and commissural vittae, relative size of vittae and vascular bundles, ratio of thickness to width of vascular bundles, ratio of thickness to width of endosperm and ratio of endosperm furrow depth to endosperm thickness.Based on our results we are able to identify and classify the species of this genus. In addition, we selected the most important characters and provided an identification key to represent the similarities and relationships between the species. Anatomical studies also confirm morphological differences between P. anthriscoides and other species of Pimpinella. Therefore, this species is affiliated into a distinct, new genus Pseudopimpinella.