Polygala tocantinensis J.F.B.Pastore & Antar, 2021

Pastore, José Floriano Barêa & Antar, Guilherme Medeiros, 2021, Two new endangered species of Polygala series Trichospermae (Polygalaceae), endemic to the Cerrado domain, Tocantins State, Brazil, European Journal of Taxonomy 762, pp. 133-148 : 137-138

Polygala tocantinensis J.F.B.Pastore & Antar sp. nov.

urn:lsid:ipni.org:names:77219130-1

Figs 4–6

Diagnosis

Polygala tocantinensis sp. nov. is similar to P. trichosperma but differs from it by its internal sepals (wings) with two glands near the rounded apex, and convergent ring of trichomes at the base of the seed (vs internal sepals without glands and with acute apex, and divergent ring of trichomes at the base of the seed in P. trichosperma ).

Etymology

The specific epithet is a reference to Tocantins State where the species is endemic. Two phytogeographic domains of the state, the Amazon and the Cerrado, are known for large areas of vegetation in a good conservation status. Even though new species from Tocantins are being continuously described (e.g., Araújo et al. 2016; Moreira et al. 2017; Barbosa-Silva & Antar 2020; Silva et al. 2020), the flora of the state is relatively poorly known ( BFG 2015) and more collecting efforts are in order.

Material examined

Type BRAZIL – Tocantins • Dianópolis, Garganta , campo rupestre, 26 May 2008; fl.; J.M. Silva, J. Cordeiro and J. Vaz 6769; holotype: CTBS[n. 2532], isotype: MBM [ MBM341152 ] .

Paratypes BRAZIL – Tocantins • Mateiros. Parque Estadual do Jalapão , Estrada entre Mateiros e povoado de Mumbuca; 10 May 2011; E. Barbosa, J. Cordeiro and J.M. Silva 3231; CTBS[n. 2553], MBM, SPF [ SPF00230503 ] • Estrada Mateiros-São Félix do Tocantins, aproximadamente 9 km de Mateiros, elevação à direita da estrada; 10º28′21.8″ S, 46º27′14.9″ W; 603 m alt.; 20 Sep. 2012; L.M. Borges et al. 855; SPF [ SPF00211698 ] • Estação Ecológica Serra Geral do Tocantins , estrada central que corta a estação ecológica ao meio; 10º59′30.5″ S, 46º44′10.6″ W; 598 m alt.; 31 Jan. 2015; G.M. Antar, H.P. Antar and U.R. Chagas 737; SPF [ SPF00220126 ] .

Description

Herbs 20–50 cm tall; roots lignose, not fleshy; stems erect, branched mostly near the apex, ± angulate, deeply costate, glabrous, green, without yellowish glands. Leaves all alternate, subsessile, chartaceous, mostly restricted to the base of stems, ocasionally nearly absent, laminas 3.2–5.2 × 0.4–0.6 mm, linear, apex acute, base acute, glabrous, margins plain. Racemes congested, 0.7–1.2 × 1–1.2 cm, up to 2.2 cm long after capsules have fallen, flowers congested; bracts 0.9–1.1 × 0.5 mm, lanceolate, apex cute, notciliate, without glands, deciduous before anthesis, ca. 1.5 times as longer as bracteoles; bracteoles ca 0.7 mm long, elliptic, not ciliate; pedicel 1.2–1.6 mm long, glabrous. Flowers lilac, purple or pinkish, 4.5–5.3 mm long (without pedicel); outer sepals not ciliate, with orange glands; lower outer sepals 1.5–1.9 × 0.6–0.8 mm, elliptic to ovate, apex acute; upper outer sepals 1.9–2.2 × 1–1.1 mm, elliptic, with orange glands at the base, apex obtuse; inner sepals (wings) 3.9–4.6 × 2.3–2.7 mm, elliptic, apex obtuse, margins not ciliate, longer than the mature fruits, with orange glands at the base and apex; lateral petals 4.1–4.2 × 0.9–1.2 mm; keel ca 3.1–3.2 mm long, cristate, with yellow glands around the dorsal central vein, deciduous on mature fruits; crest 4–6-lobed; central lobes often 2- or 3-lobed at apex; style 1.5–1.6 mm long, erect, terminated by an oblique cymbiform pre-stigmatic cavity, posterior extremity with a conspicuously crested appendage with abundant trichomes and an anterior globose stigma. Capsules 3.3–3.5 × 2.2–2.3 mm, subovate, bearing a double line of orange glands (according to Fig. 4 ) close to the central nerve, style deciduous in fruit; seeds 2.3–2.5 × 0.9–1.0 mm, subconical to obclavate, pubescent, trichomes ca 0.3 mm long, ring of trichomes at the base of the seed to 0.7 mm; caruncular appendages 1.1–1.2 × 0.1–0.2 mm reaching approximately ½ the seed length.

Distribution, habitat, and phenology

Polygala tocantinensis sp. nov. grows in open natural grasslands with scattered shrubs (campo sujo), occasionally near rocky outcrops, on sandy dry soils, sometimes recently burned, at altitudes of 410 to 820 meters alt., in the Tocantins municipalities of Dianópolis and Mateiros ( Fig. 5 ). Although considered for now endemic to Tocantins State, Polygala tocantinensis sp. nov. may also occur in the municipality of Formosa do Rio Preto, Bahia State, as the type collection was made at the division between the two states. Future collecting efforts in a similar physiognomy in Bahia State may prove successful for finding new populations of P. tocantinensis sp. nov.

Preliminary conservation status

The estimated Area of Occupancy, with just 16 km ², is low; the estimated Extent of Occurrence is 1831.048 km ². This species is known from only four collections in four different localities, with two of these located inside the protected areas of the Parque Estadual do Jalapão and Estação Ecológica Serra Geral do Tocantins. As is the case with Polygala bringelii sp. nov., these areas are still subjected to uncontrolled anthropogenic fires and are been rapidly converted to agricultural use. Although still regarded as data deficient, due to the precarious state of conservation of its suitable habitats, the species should be assessed as Endangered EN B1ab(i,ii,iii)+2ab(i,ii,iii) (IUCN 2012).

Notes

Morphologically, Polygala tocantinensis sp. nov. is most closely related to P. trichosperma , with both species sharing the oblong-elliptic capsules with yellow or orange glands along the mid vein and linear leaves. However, P. tocantinensis sp. nov. differs from P. trichorperma in the characters discussed in the diagnosis. This new species is also superficially similar to Polygala bringelii sp. nov. (see comments above).

Figures

Fig. 4. Polygala tocantinensis J.F.B.Pastore & Antar sp. nov. A. Flower. B. Bracteoles. C. Bracts. D. Two upper outer sepals. E. Lower outer sepal. F. One of the two inner sepals (wings). G. Gynoecium. H. Crest. I. Keel. J. Androecium and lateral petals. K. Fruit with persistent calyx. L. Capsule. M. Seed. All from J.M. Silva, J. Cordeiro and J. Vaz 6769. Photos: J.F.B. Pastore.

Fig. 5. Polygala tocantinensis J.F.B.Pastore & Antar sp. nov. A. Inflorescence detail. B. Habit. Photos: G.M. Antar, in situ.

Fig. 6. Geographical distribution of Polygala tocantinensis J.F.B.Pastore & Antar sp. nov. (squares). PEJ = Parque Estadual do Jalapão, EESGT = Estação Ecológica Serra Geral do Tocantins. The creamcolored portion of the insert map shows the extent of the Cerrado domain in Brazil.