Barbacenia blackii L. B. Sm.

Barbacenia blackii L. B. Smith

SPECIMENS EXAMINED.—Macedo 2962.

SURFACE VIEW.—Hairs: numerous multicellular hairs on abaxial and adaxial surfaces in variable length. Epidermis: cells square to rectangular on both surfaces; thin walled. Stomata: paracytic, 21

× 18 μm; present on adaxial and abaxial surfaces.

TRANSVERSE SECTION OF LAMINA.—Somewhat dorsiventral; V-shaped with margins turned slightly inversely. Both adaxial and abaxial surfaces slightly undulating. Epidermis: adaxial cells dome shaped, few conical; walls slightly thickened. Abaxial cells rounded to dome shaped, few conical; thin walled. Multicellular hairs present on adaxial and abaxial surfaces. Cuticle: very thin on both surfaces. Stomata: present on adaxial and abaxial surfaces; small substomatal chamber present. Mesophyll: two to three layers of palisade-like tissue grading into compactly arranged spongy tissue; translucent cells present in spongy layer. Vascular bundles: 31; few commissural bundles observed. One to three large vessels present in each vascular bundle. Two phloem units lying laterally in flanges of Y-shaped abaxial girder. Inverted Y-shaped adaxial girder present on each vascular bundle. No abaxial sclerenchyma strands observed. Each vascular bundle completely surrounded by a bundle sheath. Crystals: present. Tannins: none observed.

Barbacenia blackii L. B. Smith

Barbacenia blackii L. B. Smith, Contr. U.S. Nat. Herb., 35:283, pl. 10: figs. 31, 32, 1962.—Ayensu, Smithsonian Contr. Bot., 15:61, pls. 9c,d, 48c, 1974.

Aylthonia blackii (L. B. Smith) Menezes, Ciência e Cultura, 23(3):[421], 1971.

TYPE.—Serra do Cipó, Minas Gerais, Brazil, 13 January 1951, Pires & Black 2734 (US, holotype).

DISTRIBUTION.—Brazil: Minas Gerais: Conceição do Mato Dentro.