Paepalanthus cupreus Sauthier

Sauthier, Luana J., Tissot-Squalli, Mara L., Ramos, Renato & Sano, Paulo T., 2025, Taxonomic Revision of the Paepalanthus canastrensis Complex (Eriocaulaceae) with Descriptions of Four New Species from Serra da Canastra, Phytotaxa 708 (2), pp. 145-166 : 161-164

Paepalanthus cupreus Sauthier & Tissot-Sq., sp. nov. ( Figs. 12–13 )

Diagnosis: — Paepalanthus cupreus differs from the remaining P. subg. Platycaulon species in Serra da Canastra by the brownish red trichomes on the axil of the leaves (× stramineous trichomes) and linear leaves with 1 cm or more long cilia (× linear with cilia up to 0.5 cm in P. canastrensis ; or lanceolate to narrow-triangular leaves, without cilia in P. versatilis or with cilia up to 0.5 cm in P. canastrensis , P. aulociliatus and P. myriothrixus ).

Type: — BRAZIL. Minas Gerais: São Roque de Minas, Parque Nacional da Serra da Canastra, Chapadão do Zagaia, antes da torre de observação, a ca. 10 km da guarita de Sacramento, 20°08’33.05”S 46°48’01.86”W, elev. 1391 m, 15 November 2017, L.J. Sauthier 53 & R. Ramos (Holotype SPF barcode SPF00249574!, Isotype HUIRB!).

Perennial herb, 8–28.7 cm high, habit in rosette, stem vertical, internodes shorter than 0.5 cm, remnants of vascular bundles persistent in castaneous fibers. Leaves 3.5–27.5 × 0.2–0.7 cm, spirallate, flat, linear, without superficial wax, glabrous; apex acute to acuminate glabrous below the hydathodes area; margins ciliate with long deciduous cilia (more than 8 mm); leaf base with a paler color on the adaxial surface, membrane absent, presence of a dense indumentum on the leaf axil with brownish red trichomes. Spathe 1–4.5 cm length, green, membranous to papery, glabrous, truncate to oblique, ciliated. Scapes 6.3–17 cm long, scarcely pilose, branched, grouping free capitula. External involucral bracts lanceolate to ovate, at least one third shorter than the internal involucral bracts, dorsally glabrous to scarcely pilose, obtuse to acute, stramineous to light brown. Internal involucral bracts lanceolate to ovate, dorsally glabrous to scarcely pilose, obtuse to acute, dark brown. Flowers trimerous. Staminate flower 3–4 mm long; floral bracts 3–4 mm long, lanceolate, dorsally glabrous but densely pilose towards the apex with subclavate trichomes, obtuse to acute; sepals 2.6–3.2 mm long, oblanceolate, connate at the base, obtuse to acute; floral tube not ciliated, hyaline. Pistillate flower 2.8–4.5 mm long, pedicellate; floral bracts 2.2–4 mm long, lanceolate to oblanceolate, dorsally glabrous but densely pilose towards the apex with subclavate trichomes, obtuse to acute; sepals 2–3.8 mm long, oblanceolate, connate at the base, obtuse to acute; petals 2.2–3 mm long, obovate, obtuse to acute; gynoecium with nectariferous branches shorter than the stigmatic branches. Seed ca. 1.2–1.3 mm long, light brown to reddish brown, tegument forming white appendages after hydration.

Habitat, distribution and conservation: — Paepalanthus cupreus grows in the savannas of Chapadão do Zagaia on sandy soil ( Fig. 2 ). Just one record is reported for campos rupestres in Delfinópolis municipality. The species presents the most severe impacts of fire ( Fig. 15 ), with a more significant recurrence of fires, particularly in specific environments with hydromorphic soils. In addition, the species faces threats from boar-pig hybrids, as they turn over the substrate, ripping out individuals of P. cupreus . We encountered an estimated number of less than 250 reproductively mature individuals, indicating Endangered (EN) status, both from AOO (20 km 2) and EOO (238 km 2) ( Fig. 14 ), using criteria B1ab(iii)+2ab(iii); D.

Morphologic and taxonomic comments: —One of the morphologic variations observed in P. cupreus is the pilosity on the involucral bracts, being glabrous in some specimens or scarcely pilose with deciduous trichomes in others. The same occurs with their color tonality, varying from light brown to brown. A similar variation is found at the spathe aperture, which ranges from a truncate or oblique form to an unequal two-winged form, with one of those wings shorter. These morphologic variations are observed within individuals or across entire populations.

The cilia at the leaf margins are very long and multicellular, achieving almost 1 cm. Many other species have been reported as containing long cilia in P. subg. Platycaulon species (Tissot-Squalli 1997; Sauthier 2019). This trait along with the linear leaves and the dense brownish red trichomes at the axil of the leaf, makes P. cupreus easily recognizable.

Recently, P. uai Andrino, F.N.Costa & Sano was described from Serra da Canastra National Park and assigned to Paepalanthus ser. Paepalanthus Ruhland (Andrino et al. 2021: 129; Echternacht et al. 2021: 25). This species is distinguished by its thickened stem, ferruginous lanate hairs and a stem that accumulates leaf sheaths, linear leaves, and numerous axillary scapes shorter than or equal to the length of the leaves ( Echternacht et al. 2021). However, one of the paratypes, J. Nakajima et al. 3214 (HUFU barcode HUFU00051025) does not have many inflorescences and is very similar to P. cupreus . Echternacht et al. (2021) mentioned only the material at HUFU, but a second material deposited at UB (barcode UB0013231) shows the typically fused scape of a P. subg. Platycaulon species, with two capitula per scape only. Besides the scape, leaves dimensions, the glabrous limb with long ciliated margins and the lanceolate involucral bracts match P. cupreus . However, this specimen lacks the most diagnostic feature of P. cupreus , the brownish red trichomes on the axil of the leaves, so we have not included this material in the morphological analysis. Both P. cupreus and P. uai occur in the Chapadão do Diamante, and hybridization events are not ruled out between them.

Etymology: — Paepalanthus cupreus is named under the dense reddish brown trichomes at the leaf axil. The name is composed of the Latin word cupreus , meaning coopery or brownish red with metallic luster ( Rizzini 1955).

Additional specimens examined: — BRAZIL. Minas Gerais: São Roque de Minas, Parque Nacional da Serra da Canastra, estrada São Roque de Minas–Sacramento , a 52 km da portaria de São Roque de Minas , 7 November 2022, R. Mello-Silva 1958 et al. (SPF) ; Estrada São Roque-Sacramento , próximo a torre observação, 24 September 1996, J.N. Nakajima 2101 & R. Romero (SPF, HUFU image) ; Final da estrada do Retiro de Pedras , saída do parque, 23 February 1997, R. Romero 4009 et al. (HUFU image) ; Estrada para a Serra da Chapada , 26 October 1997, R. Romero 4580 et al. (HUFU image) ; Chapadão da Zagaia de frente para a Serra das Sete Voltas, após a torre de observação, 18 October 1997, R. Romero 4729 et al. (SPF, HUFU image) ; 21 September 2000, E.R. Salviani 1594 & H. Lorenzi (SPF); Estrada São Roque de Minas–Sacramento, a 700 m da estrada, lado esquerdo, distante 300 m a sudoeste do curral de pedras, 20º08’54.13’’S 46º47’46.1’’W, elev. 1326 m, 16 March 2020, L.J. Sauthier 180 et al. (SPF). Sacramento, Parque Nacional da Serra da Canastra , próximo à portaria de Sacramento, 67 km de Jaguarê, 01 October 1999, F.N. Costa 108 et al. (SPF) ; Guarita de Sacramento , 14 October 1994, R. Romero 1239 et al. (SPF, HUFU image) ; 24 September 1994, R. Romero 2677 et al. (SPF, HUFU image); 18 November 1995, R. Romero 3051 et al. (HUFU image). Delfinópolis, Casinha Branca , 25 October 2003, J.N. Nakajima 3664 et al. (HUFU image) .

Key to the Paepalanthus sect. Divisi species in Serra da Canastra

1. Presence of a tuft of trichomes beneath the hydathode area at the leaf apex .............................................................. P. myriothrixus

-. Absence of a tuft of trichomes beneath the hydathode area at the leaf apex......................................................................................2

2. Leaves linear.......................................................................................................................................................................................3

-. Leaves lanceolate to narrow-triangular ..............................................................................................................................................4

3. Brownish red trichomes on the axil of the leaves; cilia on leaves 1 cm or longer; involucral bracts heterogenous in color, the external light brown and the internal brown, equal to the height of the capitulum............................................................. P. cupreus

-. Stramineous trichomes on the axil of the leaves, cilia on leaves absent or up to 0.5 cm; involucral bracts homogeneously dark brown, 1/3 shorter than the high of the capitulum........................................................................................................ P. canastrensis

4. Floral tube of staminate flower ciliate; internal involucral bracts orbiculated.............................................................. P. aulociliatus

-. Floral tube of staminate flower non-ciliated; internal involucral bracts lanceolate to ovate .............................................................5

5. External involucral bracts stramineous to light brown; remnants of vascular bundles as castaneous fibers in the rosette ................. ........................................................................................................................................................................................... P. versatilis

-. External involucral bracts dark brown; vascular bundles deciduous or remaining as straw fibers in the rosette ........ P. canastrensis

Figures

FIGURE 2. Landscapes and vegetation: a) Campos Rupestres in Garagem de Pedras, Canastra; b) riverside forest and rocky outcrops in Chapadão Babilônia; c) flooded area with hydromorphic soils in Chapadão Zagaia; d) clean and gravel fields in Serra Brava. Photos by R. Ramos.

FIGURE 12. Paepalanthus cupreus, where: a) habit; b) brownish red trichomes on the axil of the leaves; c) leaf apex; d) spathe indicated by the red arrows; e) inflorescence; f) capitulum; g) external involucral bract; h) internal involucral bract; i) staminate flower; j) floral bract of the staminate flower; k) opened floral tube and sepals; l) pistillate flower; m) floral bract of the pistillate flower; n) sepals of the pistillate flower, abaxial face on the left and adaxial face on the right; o) fruit; p) petal of the pistillate flower with staminode indicated by the white arrow; q) gynoecium; r) seed. Photos a-n, p-q from L.J. Sauthier 53 & R. Ramos; o, r from F.N. Costa 108 & R. Mello-Silva Images by L.J. Sauthier and M.L. Tissot-Squalli. Scale bars equal to 1 mm, except for the staminode and seed in p and r equal to 200 μm.

FIGURE 13. Geographical distribution of Paepalanthus cupreus in the Serra da Canastra region.

FIGURE 14. Fire recurrence historical series (1980-2020), Area of Occupation (AOO) and Extent of Occurrence (EOO) of Paepalanthus subg. Platycaulon species from the Serra da Canastra region.

FIGURE 15. Impact of the fire on the Paepalanthus subg. Platycaulon species in Serra da Canastra region, measured by recurrence of burned area.