Wood and bark anatomy of Schisandraceae: implications for phylogeny, habit, and vessel evolution
Qualitative and quantitative features are reported for mature wood and bark of two species of Kadsura and five species of Schisandra. Newly reported for the family are predominance of simple perforation plates (all species); presence of pit membrane remnants in vessels of first-formed secondary xylem; two to three series of pits per facet on tracheids; diffuse axial parenchyma (Kadsura); multiseri- ate rays more than three cells wide at the widest point (all species); ethereal oil cells in axial xylem; and certain details of comparative bark anatomy. Differences in wood anatomy between Illiciaceae and Schisandraceae are nearly all differences of degree. These differences relate to the shrubby to arboreal habit in Illicium as opposed to the scandent habits in Schisandraceae. Larger pits on tracheids, wider and shorter vessel elements, and a high figure for conductive area per mm2 of transection are features related to the scandent habit of Schisandraceae; opposing character states in Illicium relate to the self-supporting nature of growth forms in that genus.