Polygala petricola J.F.B.Pastore, 2021

Pastore, J. F. B., Flaviano, S. S., Pivari, M. O. D., Anastacio, A. C. S. A. & Amano, E., 2021, POLYGALA PETRICOLA (POLYGALACEAE), A NEW SPECIES FROM BRAZIL, Edinburgh Journal of Botany 78 (356), pp. 1-7 : 2-6

Polygala petricola J.F.B.Pastore , sp. nov.

Resembling Polygala rigida A.St. -Hil. & Moq. in its yellowish flowers in short racemes and linear leaves, but easily distinguished from that species by its chartaceous leaves (versus leather-like), flower parts that are generally smaller and differently shaped ( Figure 1 ), bracts that are a little longer than the bracteoles (versus more than twice as long), internal sepals having a number of yellow spots close to the central nerve (versus without yellow spots), the base of the style being almost 1/2 the length of the style (versus a very short base, less than 1/5 of the style length), a keel with a few yellow spots close to the central vein dorsally and with short crest lobes, the central lobe c. 1 mm long (versus a keel with several yellow spots close to the central vein dorsally and long crest lobes, the central lobe c. 2 mm long). –

Type: Brazil, Minas Gerais, Brumadinho, Fazenda Cachoeira , 1158 m altitude, 20°05′49′′S, 44°01′19′′W, 29 i 2018, Paiva , J.A.M., Souza , J.A.M. & Silva, S.H.A. 1632 (holotype CTBS, isotype BHCB) .

Figures 2 , 3 .

Erect subshrub, 20–35 cm tall, roots rigid, few to many stems arising from the base, stem sparsely branched at the apex, cylindrical, striated, densely puberulous, trichomes short-clavate, stems green, without yellowish glands forming spots. Leaves all alternate, subsessile, chartaceous, lamina (8–)11–14 × (0.8–) 1.1–1.9 mm, linear to linear-elliptical, apex acute, margin revolute, base acute, densely covered by short glandular trichomes. Racemes congested 0.8–1.2 × 0.9–1.1 cm, 4.5 cm counting the part of the floral stem with the scars of the fruits fallen; bracts c.1 × 0.7 mm, lanceolate, apex acute, ciliate, trichomes glandular, with one or two yellowish spots at the base, deciduous before opening of flowers, c.1.1 times longer than bracteoles; bracteoles lanceolate, ciliate, trichomes glandular; pedicel 3.3–3.4 mm, puberulous, trichomes glandular. Flowers yellowish, 4.4–5.1 mm long (without pedicel); outer sepals ciliate, trichomes glandular, with yellow spots along the central vein; lower outer sepals 1.7–1.8 × 0.8 mm, ovate, apex acute; upper outer sepals 2.2 × 1.1 mm, elliptic, apex acute; inner sepals (wings) 3.6 × 1.7 mm, elliptic, apex acute, margins sparsely ciliate at base, longer than mature fruits, with yellow spots along the central vein; lateral petals 3.1 × 1 mm, with one yellow spot; keel c. 3.4–3.6 mm long, cristate, with yellow spots around the dorsal central vein, persistent in mature fruits; crest 4- to 6-lobed; central lobes c. 1 mm, not lobed to apex; style c. 1 mm, inclined, terminated by an oblique cymbiform prestigmatic cavity, posterior extremity with a conspicuously crested appendage with abundant trichomes and an anterior globose stigma. Capsules 3.2 × 1.7–1.8 mm, subelliptical, with several yellow spots close to the central nerve, style caducous in fruit; seeds c.2.1–2.2 × 0.8 mm, subconical, pubescent, trichomes 0.3 mm, with caruncular appendages 1 × 0.3 mm to c.1/3 of the seed length.

Distribution. The new species was collected on Serra da Moeda in the municipality of Brumadinho, Minas Gerais, near the Casa Branca District in the western part of Brumadinho, close to the municipality of Nova Lima ( Figure 4 ).

Habitat and ecology. Above 1100 m a.s.l., occurring in campo rupestre vegetation on sandy soils with rocks, on the southeast slopes of Serra da Moeda.

Flowering. The new species was collected with flowers and fruits in January, February, October and November.

Etymology. The epithet of Polygala petricola refers to its preference for rocky habitats.

Provisional IUCN conservation assessment. The only known specimens were collected within or near the area of Serra da Moeda. Two of these were collected in a legal reserve area. The extent of occurrence (EOO) and area of occupancy (AOO) were calculated using the online software GeoCat ( Bachman, 2011), resulting in 4 km 2 for the EOO and an AOO of 12 km 2. The IUCN assessment according to the criteria B: B1 and B2 a, b(iii) ( IUCN, 2012) is Critically Endangered (CR). Polygala petricola also falls within the criterion b-III of the IUCN (2012), because the region is subjected to mining activity disturbances and urban sprawl.

Additional specimens examined. BRAZIL. Minas Gerais: Brumadinho, Serra da calçada , Retiro das Pedras , –20.093056 [20°05′35′′S], –43.983611 [43°59′01′′], 11 x 2001, Viana , P.L. 304 ( BHCB); Serra da Moeda , 20°06′54′′S, 43°59′29′′W, 1417 m alt., 7 xi 2107, Souza , J.A.M. et al. 144 ( BHCB); ibid., Serra da Moeda , 20 ii 1990, Porto-Paula, L.M. & Grandi, T.S.M. 886 ( BHZB, CTBS) .

Figures

Figure 1. Comparison of the floral details of Polygala petricola J.F.B.Pastore, sp. nov., and P. rigida A.St.- Hil. & Moq. A and A′, Bract; B and B′, bracteole; C and C′, two superior outer sepals; D and D′, inferior outer sepal; E and E′, one of the two inner sepals (wings); F and F′, keel; G and G′, opened crest; H and H′, androecium and lateral petals; I and I′, gynoecium. A–I, Polygala petricola (Paiva et al. 1632, CTBS). A′–I′, Polygala rigida (Oliveira et al. 6161, CTBS). Photographs by J. F. B. Pastore.

Figure 2. Polygala petricola J.F.B.Pastore, sp. nov. A, Raceme; B, bract; C and C′, bracteoles; D, two superior outer sepals; E, inferior outer sepal; F, one of the two inner sepals (wings); G and G′, keel; H, opened crest; I and I′, androecium and lateral petals; J, gynoecium; K, fruiting calyx; L, capsule; M and M′, seed (scale bar, 1 mm). All from Paiva et al. 1632 (CTBS). Photographs by J. F. B. Pastore.

Figure 3. Polygala petricola J.F.B.Pastore, sp. nov. A, Flowers and racemes; B–D, plant and habitat. Photographs: A–C, Souza et al. 144 (CTBS); D, Paiva et al. 1632 (CTBS). Photographs: A.-C. J. A. M. Souza and D. J. A. M. Paiva.

Figure 4. Distribution of Polygala petricola J.F.B.Pastore, sp. nov.