Abarema diamantina E.Guerra, Iganci & M.P.Morim, 2016

Guerra, Ethiéne, Morim, Marli Pires & Iganci, João Ricardo Vieira, 2016, A new species of Abarema (Fabaceae) from Brazil, Phytotaxa 289 (1), pp. 77-82 : 80-81

Abarema diamantina E.Guerra, Iganci & M.P.Morim sp. nov. ( Figs. 1 , 2 and 3 )

Abarema diamantina is closely related to A. cochliacarpos , but it is distinguished by its leaflets consistency (chartaceous in the first versus membranaceous); the length of staminal tube in relation to the corolla (exserted in the first versus inserted); and the seed testa (foveolate in the first versus smooth).

Type:— BRAZIL. Bahia: Morro do Chapéu, Estrada do Feijão, trecho da estrada conhecido como Coreia, 9 a 10 km de Morro do Chapéu [ BA 052] km 259 até km 260, 11°35’44,18”S 41°04’11,10”W, 982 m elev., 21 March 2016, E. Guerra 149 (holotype ICN, isotypes RB, HUEFS).

Shrub ca. 1–2.5 m. Branches with conspicuous lenticels; petiole, rachis and rachilla with pubescent and ferruginous pulverulent indumentum. Stipules deciduous. Leaves alternate, bipinnate, 1–4 pairs of pinnae; petiole canaliculate, 5–25 mm long; rachis 13–70 mm, canaliculate; foliar nectaries sessile, orbicular and patelliform on the rachis (1– 1.4 mm in diameter), and sessile, patelliform (0.4 mm in diameter) on the rachilla; Leaflets 2–4 pairs per pinnae, opposite, sessile, chartaceous and discolorous, light green in adaxial surface, dark green in abaxial surface, obovate to oblanceolate, the proximal (8–9) 14–19 (28) × (5–9) 10–14 (17–19) mm, and the distal (20–25) 27–37 (38–42) × (12–14) 19–23 (24–25) mm, the apex rounded, sometimes emarginated, usually glabrous, sometimes puberulous on the primary veins of the abaxial surface, venation brochidodromous, secondary veins prominent on both surfaces. Inflorescences in capitate racemes, homomorphic, axillary; peduncle 65–85 mm long, with pubescent and ferruginous pulverulent indumentum; Bracteole spatuliform, 0.6 mm, pubescent. Flowers sessile; calyx campanulate 2–2.5 mm long, apex acute and puberulous; corolla campanulate 4.7–5.6 mm long, infundibuliform, apex acute and puberulous; stamens 12.3–12.6 mm, staminal tube 5.5–6 mm, exserted; anters 0.1 mm long, with rimose apertures; ovary puberulous, 1.3 mm, truncate at the apex. Legumes with spiralled valves, 170–250 × 8–14 mm, epicarp brown, with ferruginous pulverulent indumentum, endocarp brown-orange, apex acute. Seeds 7–8 × 5–6 mm, bicoloured, white and dark bluish, foveolate mostly on the distal portion, obovate; pleurogram opened, median-basal.

Distribution and habitat:— Abarema diamantina occurs in Brazil, until now it has been found only in the state of Bahia; it is restrict to the Chapada Diamantina, and it is found, up to this moment, only in the municipality of Morro do Chapéu ( Fig. 3 ).

Etymology: — The specific epithet refers to the region where the species occurs, the Chapada Diamantina, a species rich area within the Caatinga domain.

Phenology:— Old flowers and mature fruits observed in March.

Specimens examined (paratypes):— BRAZIL. Bahia: Morro do Chapéu, Distrito de Palmeiras , 11º55’S 41º15’W, 04 December 2002. M. E. R. Junqueira 169 ( HUEFS 66883 !) ; Estrada do Feijão, trecho da estrada conhecido como Coreia, 9 a 10 km de Morro do Chapéu [ BA 052 ] km 259 até km 260, 11°35’44,18”S 41°04’11,10”W, 982 m elev., 21 March 2016, E. Guerra 147 ( ICN!) ; Estrada do Feijão, trecho da estrada conhecido como Coreia, 9 a 10 km de Morro do Chapéu [ BA 052 ] km 259 até km 260, 11°35’44,18”S 41°04’11,10”W, 982 m elev., 21 March 2016, E. Guerra 148 ( ICN!) ; Estrada do Feijão, trecho da estrada conhecido como Coreia, 9 a 10 km de Morro do Chapéu [ BA 052 ] km 259 até km 260, 11°35’44,18”S 41°04’11,10”W, 982 m elev., 21 March 2016, E. Guerra 150 ( ICN!) ; Estrada para Torre , 27 April 1999, R. C. Forzza, A. M. Amorim, S. C. de Sant’ana 1397 ( SPF 136620 !) ; Serra Pé do Morro , 11°35’27S 41°12’24”W, 1293 m elev., 29 June 1996, H. P. Bautista, N. Hind, A. M. Giulietti, R. Harley, S. Smith s.n. ( SPF 130982 !) .

Comments:— Abarema diamantina shares morphological characters with A. cochliacarpos , and remarkable differences to distinguish them are shown at Table 1. Abarema cochliacarpos has wider morphological variation and geographical distribution, from Ceará state to São Paulo state. Lewis (1987) indicated the necessity of detailed studies focused on A. cochliacarpos after signalizing the existence of recognizable morphotypes in Bahia state. The morphotypes cited by Lewis (1987) were distinguished mainly by the habit height: one is restricted to the coast of Bahia (a tree of 10 m or taller), and an extreme inland form as a shrub up to 2 m, with leaflets rounded, apically emarginated, and prominent venation in both leaflet surfaces (Harley 22900). Barneby & Grimes (1996), agreed with Lewis (1987), mentioned the occurrence of a diminute morphotype, similar to those of Chapada Diamantina, in Rio de Janeiro state. Iganci & Morim (2012), recognized the morphotypes cited by Lewis (1987), and highlighted the existence of another smaller morphotype occurring in the island of Cabo Frio, in Rio de Janeiro state.

The morphological plasticity that follows Abarema cochliacarpos distribution range is noteworthy on the leaf. Characters such as number of pinnae, leaflet size, consistency and form widely vary within inland populations and when comparing inland and coastal populations. However, reproductive characters are fairly stable along its geographical range. The flowers in A. cochliacarpos have included staminal tube and the seeds have smooth testa, while the new species presents exserted staminal tube and foveolate testa. Besides the clear differences on leaf morphology of the material examined by Lewis (1987), which are more membranous (Mori 9431, from Vitória da Conquista) or coriaceous with prominent nerves (Harley 22990, from Morro do Chapéu), none of these samples present flowers with exserted staminal tubes and the seeds are not available. Thus, it is not possible to say for sure if they belong to A. diamantina . Both species do occur in the Chapada Diamantina, being the new species restrict to the Morro do Chapéu until now.

Figures

FIGURE 1. Illustration of Abarema diamantina E.Guerra, Iganci & M.P.Morim. A. Branch with fruits; B. Inflorescence; C. Flower; D. Ovary; E. Seed. (Vouchers:A, C, D—E. Guerra 147; B—M.E.R. Junqueira 169; E—E. Guerra 150). Drawn by João Iganci.

FIGURE 2. Abarema diamantina E.Guerra, Iganci & M.P.Morim.A. Habit; B. Leaflets; C. Pod; D-E. Seed.

FIGURE 3. Distribution map of Abarema diamantina E.Guerra, Iganci & M.P.Morim showing the unique location where the species is found until now, in the Bahia state.