Bark anatomy of lianescent Bignoniaceae: a generic synopsis Author Pace, Marcelo R. Author Marcati, Carmen R. Author Lohmann, Lúcia G. Author Angyalossy, Veronica text Adansonia 2023 3 2023-05-30 45 12 167 210 journal article 10.5252/adansonia2023v45a12 1639-4798 8006364 VIII. Cuspidaria - Tynanthus clade TAXONOMIC INFORMATION . — This clade contains two genera, Cuspidaria and Tynanthus , both with four phloem wedges in transversal section. While the circumscription of Tynanthus has remained constant in different classification systems, Cuspidaria currently includes species from three previously recognized genera (see Fischer et al. 2004 ; Table 1 ), Cuspidaria , Arrabidaea , and Pyrostegia . TOTAL NUMBER OF SPECIES IN THIS CLADE . — 35 species belonging to Cuspidaria (21) and Tynanthus (14) ( Lohmann & Taylor 2014 ; Medeiros & Lohmann 2015 ; Kaehler et al. 2019 ). STUDIED SPECIES . — Four species, Cuspidaria convoluta (Vell.) A.H.Gentry , C. pulchra (Cham.) L.G.Lohmann , Tynanthus cognatus (Cham.) Miers , and T. elegans (Vell.) L.G.Lohmann. Regular phloem Thin to thick fiber bands, assemblages present ( Fig. 11D ). Mostly thin fiber bands in T. cognatus ( Fig. 11D ). Variant phloem General configuration. Fibrous ( Fig. 11 A-C, E, F), with axial elements in a tangential arrangement of one row of sieve tubes, surrounded by a sieve-tube-centric phloem parenchyma ( Fig. 11 A-C). A band of parenchyma sometimes present ( Fig. 11F ). Sieve-tube elements. As seen in transverse section, each sieve element is associated with 2-3 (sometimes over 4) companion cells that occur at the same side of the sieve element ( Fig. 11B, E ). The sieve elements generally occur in multiples of 2-3 (up to 5) radially elongated cells ( Fig. 11B ). Solitary sieve elements are also present in Cuspidaria ( Fig. 11F ). As seen in transverse section, the sieve elements are of variable length, from 400 µm to approximately 1 mm and their end walls are inclined, bearing compound sieve plates with 12- 30 sieve areas ( Fig. 11G ). Axial parenchyma. The phloem parenchyma is typically sieve-tube-centric, surrounding the groups of sieve elements ( Fig. 11B, C, E, F ). In Cuspidaria convoluta , lignified lines of phloem parenchyma cross the entire phloem wedge ( Fig. 11C yellow arrows); some non-lignified lines are also found occasionally in this species ( Fig. 11F ). Fibers. Fibers are very abundant, forming background tissue ( Fig. 11 A-C, F). Rays. The limiting rays are lignified to both xylem and phloem faces ( Fig. 11A ), with a radial row non-lignified between them. The wedge rays have randomly alternating portions lignified and non-lignified. The lignified portions never bear crystals and are differentiated very close to the cambium. Crystals. Acicular and navicular crystals are present solely on the non-lignified portions of the phloem and ray parenchyma. Periderm A single periderm is formed. The phellem is stratified, composed of thin and thick-walled cells in alternation. The phelloderm is thick, with over three cell layers, non-stratified ( Table 2 ). In Tynanthus the lenticels are non-stratified, with unlignified filling tissue ( Table 2 ). In Cuspidaria the lenticels are stratified, with a closing layer of lignified cells ( Table 2 ).