Lundia

Pace, Marcelo R., Marcati, Carmen R., Lohmann, Lúcia G. & Angyalossy, Veronica, 2023, Bark anatomy of lianescent Bignoniaceae: a generic synopsis, Adansonia (3) 45 (12), pp. 167-210 : 185

VII. Lundia clade

TAXONOMIC INFORMATION. — This clade contains a single genus, Lundia , with multiple of four phloem wedges in transversal section.

TOTAL NUMBER OF SPECIES IN THIS CLADE. — 13 species ( Lohmann & Taylor 2014; Kaehler & Lohmann 2021a).

STUDIED SPECIES. — Five species, Lundia longa (Vahl) DC. , L. damazioi C.DC., L. densiflora DC. , L. virginalis DC. , and L. nitidula DC.

Regular phloem

Thin fiber bands ( Fig. 10H ) and assemblages present.

Variant phloem

General configuration. Fibrous ( Fig. 10G, I ), with axial elements in a tangential to diagonal arrangement ( Fig. 10G, I ).

Sieve-tube elements. As seen in transverse section, each sieve element is associated with one companion cell, rarely two ( Fig. 10I ). The sieve elements may be solitary to multiples of 2-3 ( Fig. 10I ). Narrower sieve elements with just one companion cell may be found in a parenchyma band present in all species studied. As seen in longitudinal section, the sieve elements are long (over 1 mm) and their end walls are inclined, bearing sieve plates with 12-15 sieve areas.

Axial parenchyma. The phloem parenchyma is sieve-tube-centric to sieve-tube-centric incomplete, therefore surrounding or partially surrounding the groups of sieve elements ( Fig. 10I ). Furthermore, a parenchyma band composed of 2-3 cells of phloem parenchyma is associated with sieve elements of narrower diameter. The phloem parenchyma tends to form radial rows of 4-6 cells in some places.

Fibers. Fibers form the background tissue where all other cells are embedded ( Fig. 10G, I ).

Rays. The limiting rays are only lignified to the xylem face (10G). The wedge rays have randomly alternating portions lignified and non-lignified.

Crystals. Acicular crystals are present in the phloem and ray parenchyma across the entire phloem wedge (absent in Lundia longa ).

Periderm

A single periderm formed. The phellem is non-stratified, composed of evenly thin-walled cells in Lundia corymbifera and L. virginalis . The phellem is stratified in Lundia longa , with alternating thin and thick-walled cells.The phelloderm is thick, with over three layers of cells, non-stratified ( Table 2 ). The lenticels are non-stratified, with unlignified filling tissue ( Table 2 ).

Figures

FIG. 10. — Secondary phloem of Manaosella, Pachyptera, and Lundia. Transverse sections: A-C, Manaosella cordifolia; A, overall view of the phloem wedge and the variant phloem of Manaosella. Stratified,non-fibrous phloem;B, fiber bands of generally three cells,some of which are tangentially very long.Rays lignify when crossing the fiber bands.Sieve tubes (arrows) diffuse;C, Sieve tubes (*) with one companion cell (arrows) lying at one corner of the sieve tube.Axial parenchyma forms the background tissue. Acicular crystals common in axial and ray parenchyma;D-F, Pachyptera aromatica; D, overall view of the regular phloem, with fiber bands formed by 3-4 polygonal fibers. Axial parenchyma forms the background tissue. Nonconducting phloem evident after the first fiber band, with collapse of sieve tubes (arrow) and dilatation of axial and ray parenchyma; E, overall view of the phloem wedge and variant phloem. Stratified, non-fibrous. Sieve tubes in radial arrangement. Axial parenchyma as the background tissue. Rays lignified when crossing the fiber bands. Fiber bands thin to thick; F, detail of the variant phloem. Sieve tubes (*) solitary or in multiples. One to two companion cells (arrows) lying to the same side of the sieve tube; G-I, Lundia; G, Lundia glazioviana. Overall view of the phloem wedge, variant and regular phloem. Fibrous phloem. Sieve tubes arranged tangentially or in clusters; H, Lundia damazioi. Regular phloem. Thin fiber bands. Axial parenchyma forms the background tissue. Tiny sieve tubes (arrows); I, Lundia damazioi. Variant phloem. Wide sieve tubes (*) solitary or in multiples.Axial parenchyma sieve-tube-centric. One to two companion cells per sieve tube,lying at the same corner of the sieve tube. Abbreviations: cz, cambial zone; fb, fiber band; lr, limiting rays; x, secondary xylem. Scale bars: A, E, 500 μm; B, D, F, I, 100 μm; C, 50 μm; G, 400 μm.