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Background and Aims: The Diervilla and Lonicera clades are members of the family Caprifoliaceae (Dipsacales sensu Donoghue et al., 2001, Harvard Papers in Botany 6: 459–479). So far, the intergeneric relationships of the Lonicera clade and the systematic position of Heptacodium remain equivocal. By studying fruit and seed morphology and anatomy, an attempt is made to clarify these issues. In addition, this study deals with the evolution of fruit and seed characters of the Diervilla and Lonicera clades with reference to allied taxa. Methods: Light and scanning electron microscopy were used for the morphological and anatomical investigations. Phylogenetic analyses were carried out by applying the parsimony and Bayesian inference optimality criteria. Character evolution was studied by means of parsimony optimization and stochastic character mapping. Key Results: Diervilla and Weigela (Diervilla clade) are characterized by several unique traits

Background and Aims: The Diervilla and Lonicera clades are members of the family Caprifoliaceae (Dipsacales sensu Donoghue et al., 2001, Harvard Papers in Botany 6: 459–479). So far, the intergeneric relationships of the Lonicera clade and the systematic position of Heptacodium remain equivocal. By studying fruit and seed morphology and anatomy, an attempt is made to clarify these issues. In addition, this study deals with the evolution of fruit and seed characters of the Diervilla and Lonicera clades with reference to allied taxa. Methods: Light and scanning electron microscopy were used for the morphological and anatomical investigations. Phylogenetic analyses were carried out by applying the parsimony and Bayesian inference optimality criteria. Character evolution was studied by means of parsimony optimization and stochastic character mapping. Key Results: Diervilla and Weigela (Diervilla clade) are characterized by several unique traits in Dipsacales, including capsules with numerous seeds, seed coats without sclerified outer tangential exotestal cell walls, and dehiscent fruits. Seeds with completely sclerified exotestal cells and fleshy fruits characterize the Lonicera clade. Leycesteria and Lonicera have berries, ovaries without sterile carpels and several seeds per locule, whereas Symphoricarpos and Triosteum have drupes, ovaries with one or two sterile carpels and a single seed per locule. Heptacodium shares several characteristics with members of the Linnina clade, e.g. achenes, single-seeded fruits and a compressed, parenchymatous seed coat. Conclusions: The results confirm the monophyly of the Diervilla and Lonicera clades and allow us to hypothesize a close relationship between Leycesteria and Lonicera and between Symphoricarpos and Triosteum. Fruit and seed morphology and anatomy point to a sister relationship of Heptacodium with the Linnina clade, rather than with the Lonicera clade.

The root anatomy of eight woody genera of the Caprifoliaceae cultivated in the British Isles was investigated. Special emphasis was placed on the characters that can most easily be used to identify roots from this family. These were found to be:(i) in the bark, the arrangement of phloem fibres or stone cells (if present) and (ii) in the xylem, the type (scalariform or simple) and shape of vessel perforation plates, type and arrangement of cells in rays and the presence or absence of spiral thickening (especially on fibre tracheids). Vessel characters were found to be inconstant in samples of some species grown in different environmental conditions.