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We conducted a comparative anatomical study of the petiole of 16 taxa belonging to the tribe Sorbarieae (Rosaceae) (Adenostoma, 2 spp.; Chamaebatiaria, 1 sp.; Sorbaria, 6 spp., 3 vars., and 1 forma; and Spiraeanthus, 1 sp.) and the related genus Lyonothamnus (1 sp. and 1 ssp.). The distal, medial and proximal regions of petioles were transversely sectioned using conventional embedding and staining methods. Cuticles, crystals, trichomes and pericyclic fiber patterns were observed and studied. Three types of vascular nodal patterns were recognized: Type 1 was seen in Chamaebatiaria, Lyonothamnus, and Spiraeanthus (simple‐trace nodal pattern with slightly curved or U‐shaped vascular bundle); type 2 was found in Adenostoma (multiple‐traces nodal pattern with free vascular bundles); and type 3 was unique to Sorbaria (bundles fused to form a siphonostele nodal pattern). Some petiolar anatomical characteristics (e.g. cuticles, crystals, trichomes, vascular nodal pattern, and pericyclic fiber patterns) were found to provide useful information for taxonomic studies within Sorbarieae. On the basis of these characteristics, a dichotomous key for identification at the generic/specific level is provided. We also report a structural change in the vascular bundles from the stem‐leaf transitional zone to the leaf medial zone. [ABSTRACT FROM AUTHOR]

The flora of Iran is rich in endemic species of Apiaceae, many of which have been poorly investigated and whose phylogenetic relationships are unknown. We investigate the relationships within five genus groups of Apiaceae subfamily Apioideae native to the Flora Iranica region using nuclear ribosomal DNA ITS sequences. Supplementary comparative data come from morphology and, for one of these groups, petiole anatomy and palynology. These groups of Apioideae are circumscribed initially on the basis of morphological similarities andlor the results of previous molecular systematic investigations, then redefined and confirmed as monophyletic based on the results of maximum parsimony, maximum likelihood, and Bayesian analyses of ITS sequences from a broader sampling of species. These five redefined groups and their constituent genera include the Cachrys group (Alococarpum, Azilia, Bilacunaria, Cachrys, Diplotaenia, Eriocycla, Perulago, Prangos), cynihocarpum group (cymbocarpum, Ducrosia, Kalakia), Ferula group (Dorerna, Perula, Leutea), Johrenia group (Holandrea, Johrenia, Johreniopsis) , and Opopanax group (Opopanax, Smyrniopsis). Azilia eryngioides is a sister group to all other members of the Cachrys group, coincident with its highly unusual morphology. The monotypic Alococarpum may be transferred into Prangos pending further study. The Cymbocarpum group is contained within tribe Tordylieae, the latter now expanded to include Cymbocarpum, and the monotypic Kalakia is submerged within Cymbocarpum. Dorema and Leutea arise from within a paraphyletic Ferula in tribe Scandiceae; nomenclatural changes are suggested, but must await supporting evidence from chloroplast DNA. Neither Johrenia nor Johreniopsis of the Johrenia group (tribe Selineae) is monophyletic, with all examined species except Johrenia golestanica arising from within a paraphyletic Holandrea. Holandrea may be transferred into Johrenia and J. golestanica may constitute a new, monotypic genus pending confirmation from further investigations. Opopanax and Smyrniopsis, traditionally treated in two tribes, are confirmed as monophyletic sister groups in the Apioid superclade. They share similar morphological attributes and are closely allied to Petroedmondia, Magydaris, and Crenosciadium. [ABSTRACT FROM AUTHOR]