Paepalanthus aulociliatus 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 : 156

Paepalanthus aulociliatus Sauthier & Tissot-Sq., sp. nov. ( Figs. 8–9 )

Diagnosis: — Paepalanthus aulociliatus differs from the remaining P. subg. Platycaulon species in Serra da Canastra by the ciliated tube (× not ciliated) and orbicular internal involucral bracts (× lanceolate to ovate). From P. trichopetalus , it differs by the narrow-triangular glabrous leaves covered by wax (× linear pilose leaves without superficial wax), the membranaceous spathe (× papery) and by the dorsally glabrous external involucral bracts (× densely pilose with persistent indumentum).

Type: — BRAZIL. Minas Gerais: São Batista do Glória, Parque Nacional da Serra da Canastra, Chapadão da Babilônia, próximo ao Trevo de Furnas (MG-050), estrada vicinal para Paraíso Achado, ca. 2 km da MG-050, lado esquerdo, 20º37’30.5’’S 46º17’51.79’’W, elev. 1058 m, 14 March 2020, L.J. Sauthier 163 et al. (Holotype SPF barcode SPF00253800!, isotype HUIRB!).

Perennial herb, 21.3–35.6 cm high, habit in rosette, stem vertical, internodes shorter than 0.5 cm, remnants of vascular bundles deciduous or absent in straw fibers. Leaves 18.8–27 × 0.7–1.8 cm, spirallate, flat, narrow-triangular, leathering, with superficial wax; apex cuspidate to acuminate glabrous below the hydathodes area; margins ciliated with short deciduous cilia; leaf base with a paler color on the adaxial surface, membrane absent. Spathe membranaceous, almost transparent, very short and inconspicuous with 0.5–2 cm long, truncated. Scapes 16–35.6 cm long, scarcely pilose, branched, grouping free capitula. External involucral bracts lanceolate to ovate, as long as or longer than the capitulum, dorsally glabrous, stramineous, obtuse to acute. Internal involucral bracts orbiculate, dorsally glabrous, obtuse to acute, brown to dark brown. Flowers trimerous. Staminate flower 2.2–4 mm; 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 2.2–3 mm long, oblanceolate, connate only up the basal one quarter, obtuse to acute; tube ciliated, hyaline. Pistillate flower 2.6–4 mm long, pedicellate; floral bracts 2.4–4 mm long, lanceolate, dorsally glabrous but densely pilose towards the apex with subclavate trichomes, obtuse to acute; sepals 2–3.5 mm long, oblanceolate, connate at the base, obtuse to acute; petals 2–3 mm long, obovate, obtuse to acute; gynoecium with nectariferous branches shorter than the stigmatic branches. Fruit loculicidal capsule. Seeds 0.8–1 mm, light brown to reddish brown, tegument forming white appendages after hydration.

Habitat, distribution and conservation: — Paepalanthus aulociliatus is only recorded in the Chapadão da Babilônia ( Fig. 9 ). It inhabits wet sandy soil in rocky fields. While AOO (16 km 2) indicates Endangered (EN) threat status, EOO (21 km 2, Fig. 14 ) indicates Critically Endangered (CR). It is a species with a restricted distribution, considering mainly low fire impact ( Fig. 15 ), with an estimate of less than 50 reproductively mature individuals; it should be classified as CR, using the B2ab(iii); D criteria.

Morphologic and taxonomic comments: —The most outstanding feature of P. aulociliatus is the ciliated tube. This trait was reported first to P. trichopetalus Körnicke (1863: 399) , an endemic species from the campos rupestres of the Diamantina municipality and its surroundings. Both are easily distinguished by the shape, pilosity, and superficial wax on the leaves, as well as the texture and length of the spathe, and by the pilosity and apex shape of the external involucral bracts.

The most similar species to P. aulociliatus is P. versatilis .Apart from the ciliated tube, they can be differentiated by the internal involucral bracts, strongly orbiculate in P. aulociliatus and ovate in P. versatilis . They also have significant geographical differences. Paepalanthus versatilis is only found in the Chapadão do Diamante, while P. aulociliatus is restricted to the eastern Chapadão da Babilônia.

Etymology: — Paepalanthus aulociliatus is named under the ciliated floral tube of the staminate flower. The name comes from the Greek word aulos, meaning tube ( Stearn 1983); and from the Latin word ciliatus, meaning endowed with hairiness on the edges or margins ( Rizzini 1955).

Additional specimens examined: — BRAZIL. Minas Gerais: São Batista do Glória. Parque Nacional da Serra da Canastra, estrada para Vale dos Canteiros , 20º32’13’’S 46º24’37’’W, elev. 1252 m, 21 October 2017, D.R. Gonzaga 1072 et al. (RB) ; Região da Represa de Furnas, estrada depois do Paraíso Perdido , 20º36’44’’S 46º19’53’’W, elev. 967 m, 25 October 2006, J.N. Nakajima 4246 et al. (SFP, HUFU image) ; Região da Represa de Furnas, estrada MG 050, Capitólio–Passos, 500 m antes do Trevo de Furnas , ca. de 15 km, em direção a Serra , 01 October 2005, R. Romero 7259 et al. (SPF, HUFU image) ; Chapadão da Babilônia, próximo ao Trevo de Furnas (MG-050). Estrada vicinal para Paraíso Achado , ca. 2 km da MG-050, lado esquerdo, 20º37’32.09’’S 46º17’52.95’’W, elev. 1064 m, 14 March 2020, L.J. Sauthier 164 et al. (SPF, HUIRB) .

Figures

FIGURE 8. Paepalanthus aulociliatus, where a) habit; b) membranaceous spathe indicated by the red arrows; c) wax on leaves; d-e) leaf apex; f-g) inflorescence; h) capitulum; i) external involucral bract; j) internal involucral bract; k) staminate flower; l) floral bract of the staminate flower; m) opened floral tube and sepals; n) pistillate flower; o) floral bract of the pistillate flower; p) sepals of the pistillate flower in adaxial view above and abaxial view bellow; q) fruit; r) petal of the pistillate flower with staminode indicated by the white arrow; s) gynoecium; t) seed. Photos a-g, m, q from L.J. Sauthier 164 et al.; h-l, n-p, r-s from L.J. Sauthier 163 et al. (SPF); t from R. Romero 7259 et al. (HUFU). Photos by L.J. Sauthier and M.L. Tissot-Squalli. Scale bars equal Scale bars equal to 1 mm, except for the staminode and seed in r and t equal to 200 μm.

FIGURE 9. Geographical distribution of Paepalanthus aulociliatus 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.