Vestured pits: their occurrence and systematic importance in eudicots

The distribution of vestured pits in secondary xylem reveals interesting pa tterns that may bear on hypotheses of phylogenetic relationships within eud icots. Vestured pits are found to be relatively widespread at the base of t he eurosids I, eurosids II, and euasterids I, but the feature probably has been lost or originated independently in several more derived branches of t hese clades. Vestured pits characterise orders Myrtales and Gentianales sen su APG; other large monophyletic taxa that consistently show vestured pits include Malpighiaceae, Polygonaceae, Brassicaceae, and most Fabaceae. Repre sentatives from euasterids Il always show nonvestured pits. The occurrence of the character implies numerous parallel origins in the following diverge nt, major taxa: (1) Proteaceae, (2) Polygonaceae (Caryophyllales). (3) euro sids I(Zygophyllaceae, Fabales, very few Rosales, Malpighiales), (4) eurosi ds II (Myrtales, Malvalus, Brassicales), and (5) euasterids I(Gentianales. Lamialus, Solanales). It is demonstrated that vestured pits frequently supp ort results from DNA data.