Huberia rubricalyx Bochorny & R. Goldenb. 2025, sp. nov.
Creators: name: Bochorny, Thuane
name: Gonella, Paulo M.
name: Gonçalves, Lucas N.
name: Völtz, Rafael R.
name: Goldenberg, Renato
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Melastomataceae
Huberia
Huberia rubricalyx

description: 5.Huberia rubricalyxBochorny & R. Goldenb. sp. nov.
Figs 3, 10, 11
Type.
BRAZIL – Minas Gerais • Conselheiro Pena, Serra do Padre Ângelo, Boa Vista (crista sul do Pico do Padre Ângelo), braço de serra ao sul da estrada de terra que corta a serra; 19°20’10.9”S, 41°34’23.8”W; 1010 m; 21 Feb. 2022; Gonella P. M., Rocha L. H., Cordeiro D. P, da Silva G. A. & Bartholomay P. R. 2992; holotype: UPCB; isotype: RB.
Diagnosis.
Huberia rubricalyx differs from Huberia comosa (R. Tav., Baumgratz & R. Goldenb.) Bochorny & Michelang. due to the branches, petioles, inflorescences, bracts, and bracteoles with sparse stalked glands, these denser on nodes (vs lacking stalked glands, except for very short comose-glandulose tufts on nodes and leaf margins); leaf blades with a subcordate base (vs obtuse or rounded), and basal acrodromous veins (vs suprabasal); ciliolate-glandular calyx margin, the purple cilia 0.3–1 mm long with globose gland heads (vs eciliolate or ciliolate-glandular, in this case minute cilia ca 0.1 mm long and lacking well-defined gland heads); stamen dorsal appendages 3–4.5 mm long (vs 1–1.2 mm); 4 - locular ovary, apex with 10 lobes, these with long stalked glands (vs 3 - locular, apex with 4 lobes, glabrous); style ca 11.5 mm long (vs 6.5–8.5 mm).
Description.
Shrubs 0.4–1 m tall; branches, petioles, inflorescences, bracts, and bracteoles sparsely covered with short stalked glands 0.2–0.5 mm long (the heads sometimes caducous). Branches terete, striate. Leaves opposite; petiole 0.6–3.5 cm long; blade 1.2–5.6 × 0.4–3 cm, ovate to broadly ovate or elliptic to broadly elliptic, apex acuminate or acute, base subcordate, margin serrulate and ciliolate-glandular (the cilia 0.5–1 mm long, glandular), papyraceous, adaxial surface glabrous, abaxial surface with sparse short stalked glands 0.1 mm long, acrodromous veins 3, with an additional faint submarginal pair, basal, main veins impressed adaxially and raised abaxially, transverse veins and reticulation visible on both surfaces. Inflorescences thyrsoids 4.5–10.7 cm long, terminal, with 10–20 flowers, usually arranged in double or compound dichasia, sometimes depauperate; bracts two, persistent, leafy, petiole 0.4–2 mm long, blade 1.5–20 × 0.3–5 mm, lanceolate; bracteoles two, persistent, 1–2 mm long, ovate to lanceolate. Flowers 5 - merous, on pedicels 2.5–11 mm long. Hypanthium 3–5.3 × 2–3 mm, campanulate, glabrous; torus glabrous. Calyx tube 0.5 mm long, red, glabrous; sepals 1–1.5 × 0.5–1.5 mm, broadly triangular, apex apiculate, margin ciliolate-glandular, the purple cilia 0.3–1 mm long, glandular, the heads globose, sometimes caducous; external teeth reduced to a thick, dorsal hump. Petals 9–12 × 4.5–7 mm, left margin (in adaxial view) white, entire, right margin (in adaxial view) white to pinkish, obovate and asymmetric, apex acuminate and apiculate, margin entire, both surfaces glabrous. Stamens 10, subisomorphic, glabrous; filaments 8.5–9.5 mm long (antesepalous) or 7.5–8.5 mm long (antepetalous), greenish; connective not prolonged below the thecae, dorsal appendages 3–4.5 mm long, yellow, linear-subulate; anthers ca 5 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 covered with long stalked glands ca 2.2 mm long; style ca 11.5 mm long, slightly curved or sigmoidal, glabrous. Capsules 3–3.5 × 3.5–4 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 rubricalyx is endemic to the quartzitic outcrops of the João Pinto Formation, in the municipalities of Alvarenga and Conselheiro Pena, in eastern Minas Gerais (Fig. 3 A, B). The species was recorded in the Serra do Padre Ângelo, around the Pico da Bela Adormecida and, to the south, in the Serra do Parado, near the district of Vista Alegre; it was also recorded in the Pico da Aliança, ca 12 km to the west. Huberia rubricalyx was found forming small populations with scattered individuals in Campo Rupestre, growing on sandy soils with organic matter both on open areas and surrounded by large rock outcrops, at elevations ranging from 980 to 1400 m.
Phenology.
Collected with flowers and fruits in February and May.
Etymology.
The epithet refers to the flowers with a red calyx.
Preliminary IUCN conservation assessment.
Critically Endangered: CR B 1 ab (iii). Huberia rubricalyx is a rare species found in very small populations with scattered individuals. The species is not recorded in any protected area, although similar habitats may be found within the undersampled Sete Salões State Park. At all sites where the species was recorded, the habitat is invaded by alien species, a situation that is aggravated by recurrent arson events. The species is also subject to the same effects of climate change mentioned for H. ciliata and H. revoluta. Similar to the latter species, the reduced distribution range (EOO of 57 km 2) combined with the severely fragmented subpopulations and the threats described support its preliminary assessment as Critically Endangered.
Additional material studied (paratypes).
BRAZIL – Minas Gerais • Conselheiro Pena, afloramento quartizítico próximo a Vista Alegre (distrito de Alvarenga); 19°23’42.30”S, 41°33’26.79”W; 980 m; 1 Feb. 2021; Gonella P. M. & Cordeiro D. P. 2084; UPCB, RB • Alvarenga, Pico da Aliança, trilha para o topo do pico; 19°23’48.28”S, 41°40’35.66”W; 1160 m; 8 May 2021; Gonella P. M. & Cordeiro D. P. 2843; UPCB, RB • Conselheiro Pena, afloramento quartizítico próximo a Vista Alegre (distrito de Alvarenga); 19°23’46.10”S, 41°33’21.67”W; 980 m; 27 Feb. 2021; Gonella P. M., Cordeiro D. P., Silva G. A., Bartholomay P. R. & Medeiros L. 2190; UPCB, RB • Conselheiro Pena, Serra do Padre Ângelo, Pico do Padre Ângelo, primeiro platô do pico, na beira do precipício; 19°40’40.97”S, 41°34’28.46”W; 1210 m; 4 May 2021; Gonella P. M. & Cordeiro D. P. 2633; UPCB, RB.
Notes.
Huberia rubricalyx is morphologically similar to H. comosa since both species have papyraceous leaf blades, glabrous torus, broadly triangular sepals with glandulose-ciliolate margins, and the ovary with a lobed apex. Apart from the differences pointed out in the diagnosis, the trichomes that are part of the comose tufts in H. comosa are short (0.1–0.2 mm long), and lack well-defined gland heads, while the stalked glands in H. rubricalyx are more delicate and shorter (0.2–0.5 mm long), with globular gland heads (these sometimes caducous). The leaves of H. comosa are sometimes verticillate, but all leaves observed in H. rubricalyx are opposite. Another difference is that H. rubricalyx is endemic to quartzitic Campo Rupestre vegetation, while H. comosa occurs in the Campos de Altitude of Serra do Brigadeiro, 200 km to the south, and on a granitic inselberg named Alto Misterioso in Espírito Santo, which is about 110 km to the east of the populations of H. rubricalyx (see Tavares et al. 2008; Bochorny and Goldenberg 2017).
Huberia rubricalyx is also similar to H. ciliata and H. mayarae, both described here. For a comparative overview between H. ciliata, H. comosa, H. mayarae, and H. rubricalyx, see Table 2.
description: Published as part of Bochorny, Thuane, Gonella, Paulo M., Gonçalves, Lucas N., Völtz, Rafael R. & Goldenberg, Renato, 2025, Five new species of Huberia (Melastomataceae) from the eastern Brazilian mountains, pp. 23-42 in Plant Ecology and Evolution 158 (1) on pages 23-42, DOI: 10.5091/plecevo.134375