Martinella

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

III. Martinella clade

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

TOTAL NUMBER OF SPECIES IN THIS CLADE. — Five species ( Kataoka & Lohmann 2021).

STUDIED SPECIES. — One species, Martinella obovata (Kunth) Bureau & K.Schum.

Regular phloem

Thin fiber bands ( Fig. 8G ), assemblages absent.

Variant phloem

General configuration. Non-fibrous ( Fig.8H ),with approximately 10 rows of sieve tubes and phloem parenchyma cells between fiber bands. The axial elements are arranged radially ( Fig. 8I ).

Sieve tube elements. As seen in transverse section, each sieve element is associated with one companion cell, sometimes two, one at each corner of the sieve element. Sieve tubes occur in radial multiples of 2-3 cells ( Fig. 8I ).

Axial parenchyma. The phloem parenchyma forms a matrix where sieve elements and fiber bands are embedded ( Fig. 8I ). Sometimes radial rows of phloem parenchyma are also detected between sieve elements.

Fibers. Fiber bands are present,composed by2-3rows of cells( Fig.8I ).

Rays. The limiting rays are lignified only to the xylem side.

Crystals. Not observed.

Periderm

Not observed.

Figures

FIG. 8. — Secondary phloem of Stizophyllum and Martinella: A-E, G-I, transverse sections: F, longitudinal radial section; A-F, Stizophyllum riparium; A, overall view of the phloem wedge, with a fibrous phloem, with alternating parenchymatic bands; B, regular phloem. Thick fiber bands, multisseriate rays; C, detail of the regular conducting phloem, showing narrow sieve tubes (arrowheads) and assemblages (arrow); D, variant phloem, fibrous, with sieve tubes solitary or in radial multiples, parenchyma band present; E, detail of the variant phloem. Sieve tubes with one to three companion cells, lying on the same side of the sieve tube (yellow arrowhead). Axial parenchyma sieve-tube-centric incomplete;F, heterocellular mixed rays, sieve tubes with compound sieve plates (arrowheads), radial sieve element present (arrow); G-I, Martinella obovata; G, regular phloem. Thin fiber bands, multisseriate rays; H, overall view of the phloem wedge, non-fibrous phloem; I, detail of the variant phloem. Sieve tubes solitary or in radial multiples. Fiber bands thin. Abbreviations: cz, cambial zone; fb, fiber bands; iw, interwedge;lr, limiting ray; pw, phloem wegde; rp, regular phloem; se, sieve element; x, secondary xylem.Scale bars:A, H, 1 mm; B, D, 200 μm; C, E, 50 μm; F, I, 100 μm; G, 500 μm.