Pachyptera

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

VI. Pachyptera clade

TAXONOMIC INFORMATION. — This clade contains a single genus, Pachyptera , with four phloem wedges in transversal section. Pachyptera currently includes species from three previously recognized genera (see Fischer et al. 2004; Table 1 ), Leucocalantha Barb. Rodr. , Mansoa , and Pachyptera .

TOTAL NUMBER OF SPECIES IN THIS CLADE. — Five species ( Francisco & Lohmann 2018).

STUDIED SPECIES. — Two species, Pachyptera aromatica (Barb. Rodr.) L.G. Lohmann , and P. kerere (Aubl.) Sandwith.

Regular phloem

Thin to thick fiber bands ( Fig. 10D ), assemblages absent.

Variant phloem

General configuration. Non-fibrous ( Fig. 10D ), with approximately 8-18 rows of sieve tubes and phloem parenchyma cells between fiber bands ( Fig. 10E ). Axial elements present a diffuse to radial arrangement ( Fig. 10E, F ).

Sieve-tube elements. As seen in transverse section, each sieve element is associated with one companion cell ( Fig. 10F ). The sieve elements occur either solitary or in multiples ( Fig. 10F ), sometimes in short groups of 2-3 cells either in tangential or radial arrangement ( Fig. 10F ). As seen in transverse section, the sieve elements are thinner than 1 mm and their end walls are inclined, bearing compound sieve plates with 6-7 sieve areas.

Axial parenchyma. The phloem parenchyma intermingles all other cells ( Fig. 10E, F ). Crystalliferous parenchyma is, moreover, found surrounding the fiber bands.

Fibers. Fiber bands are present, composed by 2-4 rows of cells ( Fig. 10E ).

Rays. The limiting rays are lignified only to the xylem face ( Fig. 10E ). The wedge rays are non-lignified, except when crossing the fiber bands.

Crystals. Acicular crystals are present in the phloem and ray parenchyma. The crystalliferous parenchyma bears prismatic crystals.

Periderm

A single periderm formed. The phellem is non-stratified, composed of evenly thick-walled cells. The phelloderm is thick, with more than three cell layers, non-stratified ( 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.