The evolution of fruit in Scandiceae subtribe Scandicinae (Apiaceae)

Abstract

Evolutionary relationships among 66 representatives of the family Apiaceae, including 37 species of tribe Scandiceae subtribe Scandicinae, were inferred from separate and combined analyses of fruit morphology and anatomy and nuclear ribosomal DNA internal transcribed spacer (ITS) sequences. Phylogenetic trees inferred from analysis of 35 fruit characters were not congruent to those derived from molecular data and, overall, had much lower bootstrap support values than the latter. Contrary to molecular data, fruit characters did not support the monophyly of subtribe Scandicinae. Fruit data do, however, corroborate the monophyly of nearly every genus within Scandicinae, the affinity of members of the "crown" clade—Anthriscus, Kozlovia (including Krasnovia and Neoconopodium), Geocaryum, Myrrhis, and Osmorhiza—that had been identified in previous molecular analyses, and the sister group relationship between the "crown" clade and the genus Scandix. Phylogenies derived from the analysis of combined ITS and fruit characters were congruent to those inferred from molecular data alone. Reconstructions of ancestral character states using the results of the combined analysis suggest that among extant Scandicinae, the fruits of Athamanta have retained the most plesiomorphic characters. Evolutionary tendencies that have occurred in the fruits of Scandicinae include the broadening of the vascular bundles and vittae, the thickening of the cuticle and epidermal cell wall, the origin of bristles from hairs, the appearance of a pedicel-like appendage, the development of a long beak, and lateral wings. These changes are interpreted as adaptations to fruit dispersal and seed defense.Key words: Apiaceae, Scandiceae subtribe Scandicinae, ITS, fruit morphology.