Vellozia sulphurea Pohl

Vellozia sulphurea Pohl

Vellozia sulphurea Pohl, Pl. Bras., 1:120, pl. 95, 1827.— Seubert in Martius, Fl. Bras., 3(1):82, 1847.—L. B. Smith, Contr. U.S. Nat. Herb., 35:265, 1962.

LEAF ANATOMY (Pohl s n).—Surface View: Hairs: few tufts present on both surfaces. Epidermis: cells on both surfaces square to rectangular; thin-walled. Stomata: tetracytic, 21 × 15 μm; present in abaxial furrows only.

Transverse Section of Lamina: Dorsiventral; widely V-shaped with median adaxial groove and margins turned downward. Adaxial surface ridged;

abaxial furrowed ¼ to ⅓ thickness of blade. Epidermis: cells square to rectangular on both surfaces; few crescent-shaped; thin-walled. Adaxial cells replaced with sclerenchyma fibers in many places. Subjacent to adaxial epidermis is 2 or 3 layers of thin-walled cells interspersed with large sclerenchyma fiber bundles of 3 or 4 layers. Below is a layer of large, thin-walled parenchyma cells. Cuticle: thick and slightly ridged on entire surface. Stomata: present in abaxial furrows only; flush with epidermal surface; small substomatal chamber present. Mesophyll: 3 or 4 layers of palisade cells followed by compactly arranged spongy tissue. One or two layers of large, translucent cells radially arranged above vascular bundles; 3 or 4 above midvein. Vascular bundles: 23; commissural bundles not observed. One or two large vessels present in each bundle, mostly one. Two phloem units lying laterally in flanges of thin, Y-shaped abaxial girder. Thin, partial adaxial girder present on each bundle. Bundle sheath completely surrounding each vascular bundle. Crystals: cuboidal, present in bundle sheath and in abaxial epidermal cells. Tannins: few present.

TYPE.—Dry rocky ground, near Arraial São João Baptista, Rio das Mortes, between Tapanhoacanga

and Padre Bento, Minas Gerais, Brazil, Pohl s n (M, holotype; F, photo 18985—leaves only).

DISTRIBUTION.—Known only from the type-collection.

72. Vellozia nivea L. B. Smith & Ayensu, new species

A V. seubertiana Goethart & Henrard et V. froesii L. B. Smith, cuibus affinis, foliorum laminis subtus dense albo-tomentosis, ovario squamis erosis obtecto differt.

Caudex ca. 5 dm high (!Joly), stout (judging by leaf-bases). Leaves with sheaths 5 cm long, yellow, densely white-tomentose outside toward apex, glabrous within; blades very narrowly triangular, filiform-attenuate, to 36 cm long, 15 mm wide at base, flat becoming inrolled on drying, densely white-tomentose beneath and at base above, margins pectinate-serrate with fine suberect 6 mm long trichomes.

Scapes terminal, 6, erect, over 20 cm long, minutely white-pubescent. Ovary ellipsoid, 13 mm long, subterete, covered with erect, erose whitish scales. Tepals elliptic, 55 mm long, violet, slightly lepidote at base and medianly. Stamens ca. 18, ca. 2 cm long, phalanges unappendaged. Style exceeding the stamens; stigmas terminal, orbicular spreading.

LEAF ANATOMY (Joly & Semir 3167).—Surface View: Hairs: single, conical hairs present on abaxial surface only. Epidermis: cells on both surfaces rectangular; thin-walled. Stomata: paracytic, some tetracytic, 27 × 15 μm; present mainly in abaxial furrows; few on adaxial and abaxial surfaces.

Transverse Section of Lamina: Dorsiventral; very widely V-shaped with almost entire margin turned down. Trichomes present on abaxial surface and in abaxial furrows. Adaxial surface almost smooth; abaxial surface furrowed ⅓ to ½ thickness of blade. Epidermis: cells on both surfaces rounded to dome-shaped; thin-walled. Subjacent to adaxial epidermis is 2 or 3 layers of rounded, thin-walled parenchyma cells. Cuticle: slightly thickened and smooth on both surfaces. Stomata: present on abaxial surface and in abaxial furrows; stomata flush with epidermal surface; substomatal chamber present. Mesophyll: very large, rounded, translucent cells present above furrows. There is little spongy mesophyll lateral to furrows. Most of mesophyll totally obliterated. Vascular bundles: 53; commissural bundles not observed. One or two large vessels present in each bundle. Two phloem units lying laterally in flanges of U-shaped abaxial girder. Adaxial cap present on each bundle. Each vascular bundle surrounded by a bundle sheath. Crystals: none observed. Tannins: few present.

Note: The adaxial sclerenchyma cap is highly extended thus approaching the sclerenchyma pattern found in Barbacenia. The extreme obliteration of the mesophyll is quite distinctive.

TYPE.—Sandy soil between rocks, km 142 of the route from Lagoa Santa to Conceição do Mato Dentro, Minas Gerais, Brazil, 21 August 1972, Joly & Semir 3167 (US, holotype; SPF, isotype).

DISTRIBUTION.—Known only from the type-locality.

Vellozia sulphurea là một loài thực vật có hoa trong họ Velloziaceae. Loài này được Pohl miêu tả khoa học đầu tiên năm 1828.