Vellozia modesta L. B. Sm. & Ayensu

Vellozia modesta L. B. Smith & Ayensu

SPECIMENS EXAMINED.—L. B. Smith, Ayensu, Hatschbach 15997; Hatschbach 27869.

SURFACE VIEW.—Hairs: absent. Epidermis: cells rounded to rectangular, thin walled. Stomata: paracytic, 21 × 15 μm; present on abaxial surface.

TRANSVERSE SECTION OF LAMINA.—Dorsiventral; widely V-shaped with small median adaxial groove; margins turned slightly inversely. Adaxial surface undulating; abaxial surface furrowed about one-half thickness of blade. Epidermis: adaxial cells mostly rectangular; abaxial cells rounded to dome shaped; cells on both surfaces thin walled. Subjacent to adaxial epidermis is one to two layers of parenchyma cells interspersed with sclerenchyma strands. Below is a layer of parenchyma cells. Cuticle: fairly thin and smooth on both surfaces. Stomata: present in furrows and on abaxial surface; substomatal chamber present; stomata associated with numerous epidermal projections in furrows. Mesophyll: three- to five-layered palisade cells changing abruptly into loosely spongy tissue. Large, translucent cells arranged radially above vascular bundles and on furrows. Vascular bundles: 38; no commissural bundles observed. One to two large vessels present in each vascular bundle, mostly one. Two phloem units arranged laterally in flanges of thin Y-shaped or partial U- or V-shaped abaxial girder. Small adaxial cap present on all bundles. Sclerenchyma strands present on abaxial side, fiber often replacing epidermal cells. Layer of parenchyma cells separating abaxial sclerenchyma strands from spongy tissue. Bundle sheath completely surrounding each vascular bundle. Crystals: not observed. Tannins: present.

NOTE: This species is very distinctive because of the arrangements of adaxial and abaxial sclerenchyma strands as well as the fusiform epidermal cells at the outer portions of the furrows.