Huberia revoluta Bochorny & R. Goldenb., 2025

4. Huberia revoluta Bochorny & R. Goldenb. sp. nov.

Figs 3 View Figure 3 , 8 View Figure 8 , 9 View Figure 9

Type.

BRAZIL – Minas Gerais • Conselheiro Pena, Serra do Padre Ângelo, Serra do Pinhão, subida para o Pico do Sossego ; 19°14’23.66”S, 41°34’52.59”W; 1285 m; 2 May 2021; Gonella P. M., Cordeiro D. P., Silva G. A., Bartholomay P. R., Ribeiro J. C. & Medeiros L. 2468; holotype: UPCB; isotype: MBML GoogleMaps .

Diagnosis.

Huberia revoluta differs from Huberia glutinosa (Cogn.) Bochorny & R. Goldenb. by the 5–8 - merous flowers on pedicels 4.5–7.5 mm long (vs 6 - merous on pedicels 2.5–3.5 mm long); calyx with triangular-subulate sepals (vs broadly triangular); petals 8–12 × 4.5–6 mm, with glabrous margin (vs 13–16 × 9–11 mm, margin with sparse stalked glands); style ca 6 mm long (vs 11–12.5 mm).

Description.

Shrubs 0.5–1.5 m tall; branches, petioles, inflorescences, bracts, and bracteoles sparsely to moderately covered with sessile glands and also with sparse stalked glands 0.5–1.2 mm long (the heads sometimes caducous). Branches terete, striate. Leaves opposite, revolute leaf blades; petiole 0.2–1 cm long; blade 1.5–6.8 × 0.5–3 cm, papyraceous, ovate or elliptic, apex acute, base obtuse to subcordate, margin serrulate-denticulate and ciliolate (each tooth ending in a short cilium, usually eglandular, but seldom glandular), adaxial surface sparsely to moderately with sessile glands 0.2–0.4 mm long, abaxial surface sparsely to moderately with sessile glands, plus stalked glands 0.5–1 mm long only on the veins, acrodromous veins 5, with an additional faint submarginal pair, basal, main veins impressed adaxially and raised abaxially, transverse veins and reticulation barely visible on both surfaces. Inflorescences dichasia 1.2–5 cm long, terminal, with 5–10 flowers, but sometimes depauperate; bracts two, non-persistent, leafy, petiole 0.4–2 mm long, blade 2–7 × 1–2.5 mm, elliptic or broadly elliptic; bracteoles two, persistent, ca 1 mm long, linear-lanceolate. Flowers 5–8 - merous, on pedicels 4.5–7.5 mm long. Hypanthium 3–6.5 × 5.5–8 mm, campanulate, vinaceous, densely covered with sessile glands 0.2–0.4 mm long, otherwise glabrous or very rarely with isolate stalked glands 0.5–1 mm long; torus glabrous. Calyx tube ca 1 mm long, vinaceous, with the same trichomes as the hypanthium, but usually with more stalked glands; sepals 2–5 × 1–2.5 mm, triangular-subulate, apex bluntly apiculate, margin ciliolate-glandular, the purple cilia 0.5 mm long, sometimes caducous; external teeth absent. Petals 8–12 × 4.5–6 mm, with a white portion close to the left margin (in adaxial view) and white to pinkish portion on the right margin, obovate and asymmetric, apex rounded to emarginate, not apiculate, margin entire, eciliolate, adaxial and abaxial surfaces glabrous. Stamens 10–16, subisomorphic, glabrous; filaments 6–7.5 mm long (antesepalous) or 5–6 mm long (antepetalous), greenish; connective not prolonged below the thecae, dorsal appendages ca 3 mm long, reddish, linear-subulate; anthers 3–4 mm long in both cycles, yellow, oblong-linear, the thecae prolonged up to 0.2 mm below the insertion of the filament, with a single, apical (but ventrally inclined) pore. Ovary 3–4 mm long, 2 / 3 basally adhered to the hypanthium, 4 - locular, apex with 10 lobes, these with stalked glands ca 2.2 mm long; style ca 6 mm long, slightly curved or sigmoidal, glabrous. Capsules 5.4–7.7 × 4.8–6.5 mm, the carpels exceeding the hypanthium length by ca 1 mm. Seeds ca 1 × 0.5 mm, elongate or oblong, raphe almost equalling the seed length, testa granulate.

Distribution and habitat.

Huberia revoluta was collected on quartzitic outcrops of the João Pinto Formation, immersed in a matrix of Semideciduous Seasonal Forests in the Doce River valley in eastern Minas Gerais (Fig. 3 A, B View Figure 3 ). The species was recorded in the Serra do Padre Ângelo, in the municipality of Conselheiro Pena, where it was found on the highest peaks, the Pico da Bela Adormecida (or Pico do Padre Ângelo) and the Pico do Sossego, and also in the municipality of Alvarenga, in the Pico da Aliança. At these peaks, the species was found in Campo Rupestre growing on sandy soils rich in organic matter and among large rock outcrops, at elevations ranging from 1250 to 1510 m. The species was found growing sympatric with other endemic and recently described species, including Pleroma brevicomosum F. S. Mey & R. Goldenb. and P. caetanoi F. S. Mey & R. Goldenb. ( Goldenberg et al. 2022).

Phenology.

Collected with flowers and fruits in February, March, and May.

Etymology.

The epithet refers to the distinct revolute leaf blades.

Preliminary IUCN conservation assessment.

Critically Endangered: CR B 1 ab (iii). Huberia revoluta is found in the three highest areas of the João Pinto Formation, all of which are currently unprotected and prone to threats that directly affect the species and its habitat, such as arson events and invasive species, especially the grass Melinis minutiflora P. Beauv. ( Gonella et al. 2015; Andrino et al. 2024). The populations at Pico da Bela Adormecida and Pico da Aliança are extremely reduced and restricted, as no more than 10 individuals have been recorded at each site, in very specific habitats at the summit of each peak. The population at Pico do Sossego is the largest and more widespread, with no more than 50 individuals being recorded scattered at elevations from 1250 to 1400 m. Given the very specific habitat at higher elevations, the species is not expected to be found in the Sete Salões State Park, the only fully protected area with Campo Rupestre in the region, whose highest point is at 1135 m elevation. As discussed for H. ciliata , the region where the species is found is prone to the effects of ongoing climatic changes, and mortality of large individuals was observed during intense droughts (Paulo M. Gonella pers. obs.). The calculated AOO (16 km 2) falls within the threshold for Endangered, while the EOO (44 km 2) supports the categorization as Critically Endangered. Here, we preliminarily assess the species as CR supported by the restricted range, small population size, severely fragmented, and the observed and projected threats that equally affect all sites where the species is found.

Additional material studied (paratypes).

BRAZIL – Minas Gerais • Conselheiro Pena, Serra do Padre Ângelo, Pico do Padre Ângelo, face sul do topo do pico ; 19°19’14.46”S, 41°34’44.04”W; 1510 m; 3 Feb. 2021; Gonella P. M. & Cordeiro D. P. 2167; UPCB GoogleMaps • Conselheiro Pena, Serra do Padre Ângelo, Pico do Padre Ângelo, face sul do topo do pico ; 19°19’14.46”S, 41°34’44,04”W; 1510 m; 15 Mar. 2021; Gonella P. M. & Cordeiro D. P. 2318; UPCB GoogleMaps • Conselheiro Pena, Pico da Bela Adormecida, Serra do Padre Ângelo, trilha de acesso ao Pico da Bela Adormecida ; 19°18’53”S, 41°34’41”W; 1300–1400 m; 11 Oct. 2022; Fernandez E., Crispim G., Queiroz G. A., Gonella P. M. & Ribeiro J. C. S. 845; CESJ, RB GoogleMaps .

Notes.

Huberia revoluta is morphologically similar to H. glutinosa since both have revolute leaf blades with non-involucrate bracts, glabrous torus, thick sepals with glandulose-ciliolate margins, and the ovary with a lobbed apex, topped with glandular trichomes. They differ by the papyraceous leaf blades in Huberia revoluta (vs membranaceous in H. glutinosa ) and the hypanthium seldom with very sparse stalked glands (vs consistently and moderately with stalked glands). Huberia glutinosa is a very rare plant, collected since 1884 in the exact same spot but nowhere else, in south-central Minas Gerais (Pico do Itacolomi, at Ouro Preto; Tavares 2005; Baumgratz et al. 2024), a habitat very similar to that of H. revoluta , but which is approximately 250 km in a straight line to the south-west of Serra da Aliança.