Cuphea venosa M.G.Facco & T.B.Cavalc., 2022

Facco, Marlon Garlet & Cavalcanti, Taciana Barbosa, 2022, Novelties in Cuphea (Lythraceae) from Serra do Espinhaço and Serra da Mantiqueira, and a key to the species from Minas Gerais state, Brazil, Phytotaxa 568 (3), pp. 267-276 : 271

2. Cuphea venosa M.G.Facco & T.B.Cavalc. , sp. nov.

Type:— BRAZIL. Minas Gerais: Itacambira, estradinha para o morro da torre repetidora, 17°04’47”S, 43°16’35”W, 1326 m, 05 February 2015, Cavalcanti, Vieira, Brauner, Pereira-Silva & Moreira 3908 (holotype CEN [00088652]! , isotypes BHCB!, K!, MO!, RB!, SPF!) . Figs. 2 , 3 .

Diagnosis:— Cuphea venosa resembles C. pseudovaccinium , from C. sect. Euandra subsect. Hilariella , and C. rubrovirens Cavalcanti (1989: 71) , from C. sect. Melvilla (Anderson ex Rafinesque 1838: 102) Koehne (1874) , but differs mainly by the presence of xylopodium (versus absent in C. pseudovaccinium and C. rubrovirens ), broadly ovate to orbicular leaves (versus narrowly ovate, ovate, to ovate-oblong in C. pseudovaccinium ), covered with onearmed cystolithic appressed trichomes, slightly pubescent veins, sometimes glandular trichomes on the main vein on the abaxial surface (versus blades nearly glabrous, one-armed trichomes appressed to erect, sometimes with sessile and inconspicuous glands, in C. pseudovaccinium ), flowers with pedicels 1.5–2 mm long (versus 2–6 mm long in C. pseudovaccinium ), floral tubes 7–8 mm long, outer surface vinaceous on the dorsal region, greenish ventrally (versus floral tubes 13–15 mm long, outer surface green or yellow-green, apex ventrally bright red in C. rubrovirens ), petals dark pink to magenta (versus bright red or red with dark purple apex in C. rubrovirens ), pistils 4.5–6.5 mm long (versus 6–8 mm long in C. pseudovaccinium ), and seeds 2–2.2 × 2.2–2.4 mm (versus 2.5–3 × 2.5–3 mm in C. rubrovirens ).

Description:—Subshrubs to shrubs 1–1.5 m tall; xylopodium present; stems erect, indumentum pubescent, eglandular trichomes white, erect, dense, <0.5 mm long, mixed with sparse glandular trichomes, purplish to greenish, <1 mm long, sometimes absent; internodes 0.5–2 cm long. Leaves opposite, rarely subalternate, chartaceous to subcoriaceous, petioles 1–2 mm long, blades 8–15 × 5–11 mm, broadly ovate to orbicular, apex acute to rounded, slightly apiculate, base cuneate to rounded, margin plane to subrevolute, glandular-ciliate and strigose, indumentum strigose on both surfaces, one-armed cystolithic appressed trichomes, slightly pubescent veins, sometimes glandular trichomes on the main vein on the abaxial surface; brochidodromous, primary and secondary veins prominent on abaxial surface. Racemes frondose to frondose-bracteose, compound; bracts similar to leaves. Flowers alternate; pedicels 1.5–2 mm long, interpetiolar, rarely axillary; bracteoles 0.7–0.8 × 0.6–0.8 mm, broadly ovate; floral tubes 7–8 × 2–2.5 mm; spur ca. 1 mm long, obtuse, horizontal; outer surface vinaceous in the dorsal region, greenish ventrally, puberulous, white eglandular trichomes, ca. 0.1 mm long, and sparce glandular trichomes 0.5–0.6 mm long, on the veins; inner surface villous behind and below the stamens, mainly on the veins; petals dark pink to magenta, two dorsal 3–4.5 × 1.3–1.8 mm, narrowly obovate, four ventral 3.5–5 × 1.5–2 mm, narrowly obovate to elliptic; stamens alternately unequal, the 3 antesepalous glabrous, the two dorsalmost short stamens villous, the others villous; vesicles absent; pistil 4.5–6.5 mm long.; ovary 2–3 mm long, glabrous; style 2–3.5 mm long, glabrous; ovules 3; nectary 0.6– 0.7 × 0.6–0.8 mm, deflexed. Seeds 2, 2–2.2 × 2.2–2.4 mm, broadly obovate, apex rounded to truncate, base cuneate, margin obtuse to slightly thickened.

Distribution and habitat:— Brazil, northern Minas Gerais state ( Fig. 3 ); “campo rupestre”, on rocky outcrops surrounded by wet grassland; 1326–1383 m elev.

Conservation status:— Cuphea venosa was categorized as Critically Endangered (CR) B1ab(ii,iii), with EOO estimates of 2.8 km ² and AOO of 12 km ². It is represented by three collections, around the city of Itacambira. The region is impacted by Eucalyptus plantations, pasture management with the introduction of exotic grasses, and the increased frequency of fires ( Martinelli & Moraes 2013).

Phenology:—Collected with flowers and fruits in February and April.

Etymology:—The specific epithet refers to the primary and secondary veins that are clearly visible and prominent on the abaxial surface of the leaves.

Paratypes:— BRAZIL. Minas Gerais: Itacambira, 7 km de Itacambira a leste da cidade, na estrada para Montes Claros, 29 November 1984, Stannard et al. CFCR 6546 (CEN!, SPF!); Itacambira, estrada Itacambira-Montes Claros, 4 km de Itacambira, subindo a chapada, 17°04’09”S, 43°20’00”W, 30 April 1997, Cavalcanti et al. 2331 (CEN!, MO!).

Notes and taxonomic affinities:— Cuphea venosa is described here from three specimens collected in the municipality of Itacambira, state of Minas Gerais, Brazil, in “campos rupestres”, located in the south of Espinhaço Septentrional.

Cuphea venosa is morphologically similar to C. pseudovaccinium , from C. sect. Euandra subsect. Hilariella , which occurs in the southernmost block, in the Espinhaço Meridional, and to C. rubrovirens , from C. sect. Melvilla , sympatric in the Itacambira ( Graham 2019). These species are compared with C. venosa in the diagnosis.

Figures

FIGURE 2. A–F. Cuphea venosa M.G.Facco & T.B.Cavalc. A. Branches; B. Detail of a branch showing leaf blades with reticulate venation; C. Flower, lateral view, petals not shown; D. Flower, longitudinal-dorsal section, petals not shown; E. Pistil with the subtending nectary; F. Seed.A–D, F: Cavalcanti et al. 3908; E: Cavalcanti et al. 2331. Scale bar. A: 5 cm; B: 4 mm; C–D: 2 mm; E–F: 1 mm.

FIGURE 3. Geographical distribution of Cuphea dryadica M.G.Facco & T.B.Cavalc. and Cuphea venosa M.G.Facco & T.B.Cavalc. (MG = Minas Gerais state). Source: Topodata database (Valeriano & Rossetti 2012); IBGE (2021); SISEMA (2021).