Bonamia campestris A.Moreira & Sim.

Moreira, André Luiz Da Costa, Antar, Guilherme Medeiros, Simão-Bianchini, Rosângela & Cavalcanti, Taciana Barbosa, 2017, Contribution to the knowledge of Bonamia (Convolvulaceae) in Brazil: a new species and a new occurrence, Phytotaxa 306 (2), pp. 146-152 : 147-149

Bonamia campestris A.Moreira & Sim. -Bianch., sp. nov. ( Fig. 1 )

Diagnosis:— Bonamia campestris resembles Bonamia sphaerocephala (Dammer) Ooststr. and Bonamia capitata (Damner) Ooststr. in possessing elliptic leaves and clustered terminal inflorescences, but differs by its prostrate rather than erect habit and glabrous rather than pubescent leaves.

Type:— BRAZIL. Tocantins: Ponte Alta do Tocantins, Campos Belos, 29 May 2008, J.M. Silva, J. Cordeiro & J. Vaz 6838 (holotype: SP!, isotypes: MBM!, SPF!).

Perennial herbs, prostrate. Stems glabrous; internodes (0.2) 0.5–1.5 cm long. Leaves sessile to shortly petiolate, glabrous; blades 1.5–3.0 X 0.9–1.8 cm, elliptic; margin slightly revolute abaxially, entire; base rounded, rarely truncate or cordate; apex obtuse, mucronate, mucro ca. 1 mm long; main vein and secondary veins evident abaxially, venation camptodromous; petiole 0.5–2 mm long. Inflorescences terminal, glomerule-like, ca. 20 flowers; peduncules 2–4 mm long; pedicels glabrous, 0.5–2.5 mm long; bracteoles linear, 0.5–1.8 cm long. Calyx persistent, sepals unequal, imbricate, glabrous, margin hyaline; external sepals 5–7 × 1.5–3 mm, apex acuminate, acumem ca. 0.7 mm long; internal sepals obovate, 5–7 × 3.5–6 mm, apex rounded, mucronulate, mucron ca. 1 mm long. Corolla tubularcampanulate, 0.8–1.2 cm long, lilac; midpetaline bands glabrous. Stamens epipetalous ca. 5 mm long, filaments ca. 4 mm long, glabrous, anthers elliptic ca. 1 mm long. Ovary conical, glabrous, 2–locular, ca. 2 mm long; styles 2, 0.7–1 cm long, the basal portion fused; stigma capitate. Capsule ovoid, yellowish, opening by 2 valves. Seeds 3–4, brown, 0.3–0.5 ×. 0.1 mm, glabrous.

Phenology:— Bonamia campestris was found with both flowers and fruits in May, at the end of the Cerrado rainy season.

Habitat and distribution:— Bonamia campestris is so far only known from the municipality of Ponte Alta do Tocantins in the Jalapão region at altitudes of 400 to 600 meters, where it grows in open grasslands, “campo sujo” or “cerrado sensu stricto ”, on dry sandy soils. However, as the Jalapão region is poorly studied floristically, it may prove to be more widely distributed.

Etimology:—The epithet highlights the type of vegetation in which the species naturally occurs. Although several species of Convolvulaceae are common in open grassland vegetation, most Bonamia species grow on the edges of forests or in scrub savanna.

Conservation status:—Due to our limited knowledge of the distribution of Bonamia campestris , it is not possible to determine the conservation status of the species. The only known collection was not made in a protected area but it is likely that other populations occur in nearby areas that enjoy protection. However, the rapid expansion of the agricultural frontier has already replaced nearby cerrado areas in western Bahia ( Borges & Antar 2016) and threatens the vegetation of the Jalapão region.

Similar species and remarks:— Bonamia campestris is clearly distinguished from other species with terminal glomerule-like inflorescences by its elliptic, glabrous leaves with obtuse apices. Bonamia capitata ( Dammer 1897:36) Ooststroom (1936: 212) and Bonamia sphaerocephala ( Dammer 1897: 37) Ooststroom (1936: 212) , the most similar species morphologically, differ by their hirsute leaves and erect habit in contrast to the glabrous leaves and prostrate habit of Bonamia campestris . Bonamia balansae Hallier f. (1893: 512) is a glabrescent plant with prostrate or erect stems, but the flowers are few and arranged in axillary cymes, which differ from the dense, many-flowered inflorescence of B. campestris .

Figures

FIGURE 1. Bonamia campestris A.Moreira & Sim.-Bianch., A: Inflorescence, B: Abaxial surface of leaf, C: Bract, D: External sepal, E: Internal sepal, F: Corolla, G: Style, H: Fruit, I: Seed, J: Habit. Drawing by Laura Montserrat.