Manaosella

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 : 182-185

V. Manaosella clade

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

TOTAL NUMBER OF SPECIES IN THIS CLADE. — One species.

STUDIED SPECIES. — One species, Manaosella cordifolia (DC.) A.H. Gentry.

Regular phloem

Thin to thick fiber bands, fibers tangentially elongated in some portions, assemblages absent.

Variant phloem

General configuration. Non-fibrous ( Fig. 10A ), with approximately 14-16 rows of sieve tubes and phloem parenchyma cells between fiber bands. The axial elements present a diffuse arrangement, sometimes with a radial tendency ( Fig. 10 A-C).

Sieve-tube elements. As seen in transverse section, each sieve element is associated with one companion cell ( Fig. 10C ). Sieve tubes of two distinct diameters occur adjacent to one another and are predominantly solitary ( Fig. 10B, C ), occasionally radially disposed and arranged in multiples of 2-3. As seen in longitudinal section, the sieve elements are thinner than 1 mm and their end walls are inclined, bearing sieve plates with 7-15 sieve areas.

Axial parenchyma. The phloem parenchyma forms a matrix in which sieve elements and fiber bands are embedded ( Fig. 10 AC). Sometimes radial rows of phloem parenchyma can be also detected between or next to sieve elements ( Fig. 10B, C ).

Fibers. The fiber bands in Manaosella bear cells that are conspicuously radially elongated ( Fig. 10B ), a feature not found in any other Bignonieae genus. The fiber bands are composed of 2-3 rows of cells, with the cells located in the center or upper portions of the band radially elongated.

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

Crystals. Acicular crystals are very abundant and are found in most cells of the phloem and ray parenchyma ( Fig. 10C ).

Periderm

A single periderm formed. The phellem is stratified, composed of thin and thick-walled cells in alternation. The phelloderm is thin, with less than three layers of cells, non-stratified ( Table 2 ). Lenticels non-stratified, unlignified.

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.