S. Carlquist, Wood and stem anatomy of Stegnosperma (Caryophyllales); phylogenetic relationships; nature of lateral meristems and successive cambial activity, IAWA J, 20(2), 1999, pp. 149-163
Wood and bark histology data on stems of two species of Stegnosperma (Stegn
ospermataceae, or Phytolaccaceae s.l.) is presented, complementing previous
accounts. Wood of Stegnosperma is relatively primitive within Caryophyllal
es because of presence of tracheids, diffuse parenchyma, and both multiseri
ate and uniseriate rays. The solitary nature of vessels is held to be corre
lated with tracheid presence, as in other groups of dicotyledons with vesse
ls solitary or nearly so. Bark anatomy is newly reported for the genus. The
method of section used permits analysis of divisions in cells with primary
walls. Radial rows of parenchyma ('secondary cortex') develop in the inner
cortex and an perpetuated by tangential divisions collectively termed a di
ffuse lateral meristem here. Successive cambia form within the radial rows
of parenchyma. Despite diverse terminology and interpretations in literatur
e on plants with successive cambia, the successive cambia and their origin
in Stegnosperma are believed to represent the same anatomical phenomena as
in other Phytolaccaceae s.l.