Mimosa bahiana J. Gelma, L.P. Queiroz & Van den Berg, 2023

Do Nascimento, Janaína Gelma A., Rocha, Lamarck, Dutra, Valquíria F., De Queiroz, Luciano P. & Berg, Cássio Van Den, 2023, Four new species of Mimosa sect. Batocaulon ser. Cordistipulae (Leguminosae) from Bahia, Brazil, Phytotaxa 599 (5), pp. 265-279 : 266-269

1. Mimosa bahiana J. Gelma, L.P. Queiroz & Van den Berg , sp. nov. Figs. 1A–I , 5 .

Type:— BRAZIL. Bahia: Município de Piat „, Platô alto da Serra da Tromba , 13°07’S, 41°49’W, 2 November 1996 (fl., fr.), L.P. Queiroz et al. 4713 (holotype: HUEFS [barcode 200008832]!) .

Affinis M. setuligera Harms (1908: 208) et M. brevipinna (1875: 432) foliis 5−14-pinnatis, sed a M. setuligera stipulis inflexis, paleaceis (nec reflexis, membranaceis), foliolulis 0.8−1.2 mm longis (nec 1.8−2.7 mm longis), corolla glabra (nec tubo glabro et lobis trichomata indutis), et a M. brevipinna foliolis 0.8–1.2 × 0.6–0.7 mm (nec 3–3.5 × 1–1.5 mm), calyce 0.3 mm (nec 0.5–0.6 mm), fructibus cum 2–3-articulis (nec 6–8-articulis) differt.

Subshrubs 5–30 cm tall, prostrate or erect; branches cylindrical, velutinous, with filiform trichomes, and glandular capitate-filiform trichomes, 0.2–1.4 mm long. Internodes c. 15 mm long. Stipules 4–5 × 1–1.2 mm, lanceolate, base truncate, apex acuminate, margin ciliate, 3–5-veined. Petiole 6–8 mm long, rachis 25–35 mm long, first interpinnal segment 3.5–6 mm long, remaining segments 2–3 mm long; pinnae 6–10 pairs, median pinna 5–7 mm long, slightly decreasing in size toward the apex and the base of the leaf; leaflets 6–8(–10) pairs per pinna (median pinna), membranaceous, 0.8–1.2 × 0.6–0.7 mm, oblong, apex obtuse, base rounded, both surfaces pilose to villous, margin ciliate or sericeous, 3-veined. Capitula 10–12 mm diam., 30–35-flowered; peduncle 25–30 mm long; bracts 1–1.2 × 0.3–0.5 mm, membranaceous, linear or spatulate. Flowers sessile; calyx white, ca. 0.3 mm long, campanulate, lobes with apex truncate; corolla white, glabrous, subtubular, membranaceous, tube 0.8–1 mm long, lobes 1–1.2 mm long, acuminate; stamens 6, filaments 4–6 mm long, anthers 0.4–0.6 mm long, globose, yellow; ovary ca. 1 mm long, covered by capitate-filiform glandular trichomes, 3–4-ovulate, style 2–4 mm long. Craspedium 10–12 × 4–4.5 mm, subsessile, linear, margin undulate, puberulous, with filiform and capitate-filiform glandular trichomes, 2–3-articulate, apical and basal articles triangular, median articles rectangular, 2–3 × 4–5 mm. Seeds 2–2.5 × 1–1.5 mm, external surface smooth.

Distribution, habitat and phenology:— Mimosa bahiana is known only from the municipality of Piat„, in the southern portion of the Chapada Diamantina, Bahia, Brazil ( Figure 5 ). It was collected in “cerrado sensu stricto ” and “campos gerais” (savanna vegetation), at 1,200 –1,400 m of elevation, with flowers and fruits in November.

Conservation:— Mimosa bahiana is known from only two collections carried out in 1996. The areas where it occurs have been cleared for coffee plantation by small family groups. Due to the lack of data on the distribution of the species, we propose this species to be Data Deficient (DD).

Etymology:— The specific epithet bahiana denotes the restricted species’ geographical distribution, until now known only from the state of Bahia, Brazil.

Notes:— Mimosa bahiana is morphologically similar to M. brevipinna and M. setuligera with which it shares the multipinnate leaves with short pinnae and rather few leaflets per pinna. It can be distinguished by those two species by the branches with a velutinous indumentum (vs. glabrous or glabrescent in M. brevipinna and viscid and tomentose in M. setuligera ), leaflets smaller, 0.8–1.2 mm long (vs. 3–3.5 mm long and 1.8–2.7 mm long, respectively), and calyx smaller, ca. 0.3 mm long (vs. 0.4–1 mm and 0.5–0.6 mm, respectively). Mimosa bahiana also has smaller craspedia, measuring 10–12 × 4–4.5 mm, 2–3-articulated, and with short trichomes, mixed with glandular ones, while M. brevipinna has craspedia measuring 25–30 × 6–25 mm, 6–8-articulated and velutine ( Table 1 ). The presence of lanceolate, non-reflexed stipules, and glabrous corolla also differs from M. setuligera (narrowly lanceolate, reflexed stipules, and hispidulous corolla lobes).

Mimosa bahiana is a locally rare plant, being known only from the top of a mountain near the Piat„ town, in the southern portion of Chapada Diamantina, at more than 1,200 m of elevation. The local vegetation is an open field with few trees and subject to fire on deep sandy soil. The two most similar species, M. setuligera and M. brevipinna , do not occur in sympatry, being recorded in lowland dry scrubs on sandy soil, at elevation ranging from 200 to 400 m.

Paratype:— BRAZIL. Bahia: Piat „, estrada Piat „/Inúbia, a 2 km do entroncamento com entroncamento Piat„ / Boninal, 13°04’19’’S, 41°47’33’’W, 11 November 1996 (fl., fr.), D.J.N. Hind et al. 4184 ( ALCB) .

Figures

FIGURE 1. Mimosa bahiana. A. flowering branch. B. detail of the root. C. portion of the branch showing stipule. D. detail of the branch indument, showing simple trichomes. E. pinnae in adaxial surface. F–G. leaflets showing adaxial (F) and abaxial (G) surfaces. H. flower. I. craspedium (Drawing from Queiroz 4713, holotype—HUEFS, by Carla Lima).

FIGURE 5. Distribution map of new species of Mimosa ser. Cordistipulae from Bahia.