FIG. 9 in Bark anatomy of lianescent Bignoniaceae: a generic synopsis

FIG. 9. — Secondary phloem of Pleonotoma: A, B, D-F, transverse sections; C, longitudinal radial section; A-C, E, F, Pleonotoma tetraquetra; D, Pleonotoma melioides; A, overall view of the regular phloem. Sclerenchyma formed exclusively by sclereids, differentiating next to the cambial zone, in the conducting phloem; B, detail of the conducting phloem, sieve tubes are very narrow. Sclereids differentiating. Acicular crystals present in axial and ray parenchyma; C, heterocellular rays. Sclereids differentiating from axial parenchyma cells, close to the cambium. Mature sclereids also present; D, overall view of the phloem wedge, fibrous phloem; E, variant phloem marked by rectangular fibers, sieve tubes solitary or in radial and tangential multiples of 2-3, parenchyma sieve-tube-centric; F, detail of variant phloem. Sieve tubes with one or two companion cells lying on the same side of the sieve tube. Axial parenchyma sieve-tube-centric. Prismatic crystals present in both axial and ray parenchyma cells. Scale bars: A, C, 200 μm; B, F, 50 μm; D, 500 μm; E, 100 μm.