Turnera carolina M.J.C.Silva & L.Rocha, 2023

Turnera carolina M.J.C.Silva & L.Rocha , sp. nov. TYPE: BRAZIL. Maranhao ~: Mun. Carolina, Morro Redondo , 7 05 9 50,4 99 S, 47 26 9 36,6 99 W, 500 m, 25 Feb 2022 (fl., fr.), M.J.C. Silva & A.W.C. Ferreira 506 (holotype: MG!; isotypes: HUEFS!, MAR!, RB!).

Turnera carolina is similar to T. vallsii Arbo in the general vegetative aspect, in the flowers with the corolla shorter or as long as the calyx (# 1–1.2 mm), in the stamens glabrous, and styles pilose only on the distal portion, but differs in the leaves being nut-brownish in sicco (vs. brown-grayish in T. valssii ), petioles 5–7 mm long (vs. 1–3 mm), adaxial surface of leaves sparsely pilose (vs. tomentose), leaf blades with 6–7 pairs of secondary veins (vs. 4–5) with an angle of ca. 20 (vs. 40–50) apart from the main vein, extrafloral nectaries present in all leaves (vs. absent in basal leaves) with 0.4–0.7 mm diam (vs. up to 0.2 mm), and the calyx 7–8 mm long (vs. 4–5.8 mm).

Subshrubs or herbs ca. 60 cm tall, basal portion brown, with some cracks, glabrescent or sparsely pilose, distal portion olive-green, densely pilose, covered with simple, flexible, patent, hyaline-golden, tector trichomes; internodes (2–)2.6– 4.5(–5) cm long; leaf scars prominent. Leaves chartaceous, discolored; stipules reduced to colleters, conical, ca. 0.3– 0.5 mm long; petioles 5–7 mm long, indument like that of the young stems; extrafloral nectaries basilaminar, present in all leaves, 1 pair per leaf, 0.4–0.7 mm width, elliptical, opposite, oriented downward, dark-brown, margins with microtrichomes, adaxial surface with pore slightly evident; blades 3–8.8 3 1.4–2.5 cm (length: width 5 2.1–3.5:1), elliptic, base attenuate, apex acute, margins plane, doubly serrate to serrate-crenate, teeth usually broad, ca. 2 mm long; adaxial surface dark green in vivo, nut-brownish in sicco, covered with dark spots, sparsely pilose, with sparse, simple, flexible, tector trichomes, concentrated on the main veins; abaxial surface green-whitish in vivo, whitish-brown in sicco, entirely and markedly covered with dark spots, velutinous, with simple, curved or erect, tector trichomes, the longest concentrated on the veins; venation eucamptodromous, secondary veins in 6–7 pairs, slightly curved and sunken in the adaxial surface, prominent in the abaxial surface, ca. 20 divergent from the main vein, thinning towards the blade margin, tertiary veins visible. Flowers heterostylous, axillary, epiphyllous, and congested, forming apical or axillary racemes; floral peduncle 1.5–2 mm long, entirely adnate to bract petiole; pedicel absent; bracts leafy, 5–6 3 1–2.6 mm, lanceolate to obovate, margin serrulate, apex acute or rarely obtuse, both surfaces pilose to densely hirsute, reddish in vivo, pilose; extrafloral nectaries in 1–2 pairs, inserted in the mid-basal portion of bract blades, discoid to ellipsoid, sometimes stipitate, 0.8–1 mm width, proximal pair ca. 0.4 mm diam; bracteoles (prophylls) 1 pair, 2.2–4 3 ca. 0.5 mm, inserted below the calyx, subulate, margins entire, apex acute, both surfaces hirsute. Calyx reddish in vivo, 7–8 mm long, cylindrical campanulate, with a constriction in the apical portion of the tube; calyx tube 3.5–4 mm long, externally minutely pilose, with simple tector trichomes of variable length, internally hirsute up to the throat; calyx lobes ca. 3–3.5 3 1 mm, triangular to narrowly triangular, 3-nervate, externally hirsute, apex acute, with an apical mucron ca. 1 mm long. Corolla 6.2–7 3 1–1.2 mm; petals orange, claw hirsute on the midrib to the midportion of the blade, blade narrowly obovate, apex mucronate, apical mucron ca. 0.2 mm long. Stamens, epiphyllous; filaments subulate, ca. 7 mm long in short-styled flowers, ca. 5 mm in long-styled flowers, glabrous, flattened dorsiventrally, basidorsally adnate ca. 0.5 mm long to the floral tube; anthers ca. 1.1 3 0.7 mm, glabrous, ovoid, base emarginate, apex obtuse, straight, basidorsally fixed, mucron ca. 0.2 mm long, hyaline. Ovary ca. 1.5 mm long, ovoid, externally tomentose-hirsute, 3-carpellate, unilocular, placentation parietal; styles 3, ca. 4 mm long in short-styled flowers, ca. 6 mm long in long-styled flowers, pilose only on the distal portion; stigmas brush-like. Fruit a loculicidal capsule, ca. 3–4 3 3.5 mm, ovoid; exocarp smooth, sparsely pilose, with simple tector trichomes with brown bases; internally glabrous, glossy, placental vein prominent. Seeds ca. 2.4 3 1.2 mm, obovate, slightly curved; exostome slightly prominent, hemispherical; raphe linear; chalaza rounded, slightly prominent and obtuse; episperm reticulate, reticule nodes slightly prominent; areoles concave, quadrangular to hexagonal; epidermis with epicuticular wax filiform; aril whitish, ca. 2 mm long, margin lacerate, surface smooth. Figures 1–3 View FIG View FIG View FIG .

Etymology —The epithet refers to Carolina, the municipality of Maranh ~ ao, Brazil, where the collection sites are located.

Suggested Vernacular Name — Turnera melochioides Cambess. , a species that is sympatric with and similar to T. carolina , is locally known as “malva-brava,” in Portuguese, in reference to its similarity with some local Malvaceae species. Here we suggest, for T. carolina , the vernacular name “malvabrava-vermelha,” in reference to its reddish bracts and calices that stand out in the field.

Distribution and Habitat — Turnera carolina is known from two subpopulations ca. 15 km apart from each other, in the Chapada das Mesas region, southwestern Maranh ~ ao, Brazil ( Fig. 4 View FIG ), growing in a rupestrian cerrado vegetation, characterized by both herbaceous and woody layers, as typical for savannas, but growing on rocky, well-drained soil, interspersed with rocky outcrops (AVS pers. obs.). According to Saraiva et al. (2020), 25% of the flora of the rupestrian cerrado from Chapada das Mesas are composed of endemic plants, exemplified by the recently described Dyckia maranhensis Guarçoni & Saraiva ( Guarçoni et al. 2020).

Provisionary Conservation Status Assessment —The southwestern region of Maranh ~ ao, where the Chapada das Mesas is located, belongs to an agricultural frontier in which areas of the Cerrado are constantly under activities of deforestation. Only one of the known subpopulations of Turnera carolina is encompassed by a protected area, i.e. the Chapada das Mesas National Park, whereas the other occurs in one of the most touristic spots in the region, suffering constant human disturbance to the habitat. Based on IUCN (2012), if an evaluation were performed, this species would likely be classified as Critically Endangered (CR), meeting criterion B1ab(i, ii, iii). The species has an EOO (5 AOO) of 12 km 2, with only one location known, and with inferred continuing decline of its extent of occurrence, area of occupancy, and area and extent of quality of habitat, due to observed frequent fire, cattle grazing, and agricultural activities.

Phenology — Turnera carolina was collected with flowers and fruits in January, February, and June.

Comments — Turnera carolina belongs to T. ser. Leiocarpae Urb., due to the presence of epiphyllous flowers ( Fig. 1I View FIG ), staminal filaments basidorsally adnate to the floral tube ( Fig. 1K View FIG ), and smooth exocarp ( Figs. 1O View FIG , 3A–B View FIG ). Turnera carolina is morphologically close to T. vallsii , which also belongs to T. ser. Leiocarpae , in the general vegetative aspect, in the flowers with the corolla shorter or as long as the calyx ( Figs. 1I–J View FIG , 2C–E View FIG ), and in the stamens entirely glabrous and styles pilose only on the distal portion ( Fig. 1K–M View FIG ); both species are also restricted to the Cerrado ( Arbo 2008). The main differences between these species are in the leaf color in sicco (nut-brownish in T. carolina vs. brown-grayish in T. valsii ); in the petiole length (5–7 mm vs. 1–3 mm); in the adaxial leaf surface indumentum (sparsely pilose vs. tomentose); in the number of secondary veins on leaf blades (6–7 pairs vs. 4–5 pairs), and their divergence angle from the main vein (ca. 20 vs. 40–50); in leaf extrafloral nectaries distribution (present in all leaves vs. absent in basal leaves), and dimensions (0.4–0.7 mm diam vs. up to 0.2 mm); and in the calyx length (7–8 mm vs. 4–5.8 mm).

The vegetative aspect of T. carolina also resembles that of T. melochioides and T. angelicae Arbo , both belonging to T. ser. Leiocarpae , but these species differ in the trichomes being exclusively simple in T. carolina (vs. glandular, minutely capitate in T. melochioides and T. angelicae ); in the sepals and bracts being reddish in T. carolina (vs. green in the other two species); and in the corolla being usually orange and shorter than the calyx in T. carolina (vs. yellow and longer than the calyx in the other species,. 0.7 mm in T. angelicae , and with same length or up to 4 mm in T. melochioides ). In addition, T. angelicae presents petals entirely pilose (vs. claw hirsute on the midrib to the midportion of the blade in T. carolina ), filaments pilose (vs. glabrous), and anthers with acute apex (vs. obtuse). Among the species similar to T. carolina , only T. melochioides occurs in Chapada das Mesas, whereas T. vallsii and T. angelicae are restricted to the Cerrado of Goias, central Brazil (Flora e Funga do Brasil 2022). Differences between T. carolina and similar species are summarized in Table 1.

Additional Specimens (Paratypes) Examined — Brazil. — MARANHÃO: Mun. Carolina, 31 km da cidade na estrada para Estreito (MA 010), entrada a esquerda do Balneario Chico de Dodo, 07 05 9 46 99 S, 47 26 9 59 99 W, 246 m, 29 Jan 2012, (fl., fr), R.M. Harley, A.M. Giulietti, C. Lima, C. Silva & R.F.

Machado 56618 (HUEFS); Carolina, PARNA Chapada das Mesas, cerrado rupestre, trilha para a cachoeira do por ~ ao, 6 59 9 11.9 99 S, 47 22 9 10.3 99 W, 263 m, 03 Jun 2022, (fl., fr), M. Salazar-Ferreira, A.V. Scatigna & A.G. Nunes 158 (BMA, SLUI).