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.