Paepalanthus calvescens L.E.F. Silva & Trovó, 2019

Silva, Lucas Espindola Florêncio Da & Trovó, Marcelo, 2019, Paepalanthus calvescens (Eriocaulaceae), a new species from Espírito Santo, Brazil, Phytotaxa 397 (2), pp. 193-198 : 193-197

Paepalanthus calvescens L.E.F. Silva & Trovó , sp. nov. Figs. 1 & 2 .

Differs from Paepalanthus capixaba especially by its leaves, spathes, and scapes with very short adpressed trichomes, to usually glabrescent or glabrous.Also distinguished by its discoid to hemispherical capitula, obovate to narrowly elliptical or rarely obtrullate floral bracts with acuminate apex, larger flowers ca. 4.5 mm long, sepals of staminate flowers with obtuse to acuminate apex, and sepals of pistillate flowers with acuminate to mucronate apex.

Type: — BRAZIL. Espírito Santo: Vargem Alta, estrada vicinal que liga a rodovia ES 164 à rodovia ES 383, nos arredores do Parque Estadual da Pedra Azul , coord. - 20.452811S, - 40.998133W, 24.IX.2016, L. E. F. Silva et al. 47 (holotype RB; isotypes B, NY, P, R, SPF, VIES) .

Herbs, usually forming clumps or solitary, 23.7 − 38.5 cm tall; rhizome present, usually conspicuous, aerial stem ca. 2.0 − 3.0 cm long. Leaves persistent, chartaceous, lanceolate, dark green, flat, patent, 13.7 − 30.3 × 1.0 − 2.4 cm, with very short adpressed trichomes along the blade and rarely long trichomes close to the base margin to usually glabrescent or glabrous on both surfaces, margins glabrous to ciliate at the base, apex acute. Spathes 5.1 − 10.9 cm long, with short adpressed trichomes to usually glabrescent or glabrous on the abaxial surface, apex glabrous, acute. Scapes 7 − 48, arranged in a single terminal cohort, usually surrounded by a few axillary cohorts, 12.8 − 29.2 cm long, glabrous, multicostate. Capitula 6 − 12 mm diam., discoid to hemispherical, pale yellow to brown when old; involucral bracts in 3 − 5 series, castaneous, ovate to elliptical, ca. 3 mm long, glabrous, ciliate, apex obtuse to mucronate; receptacle hemispherical, pilose. Flowers trimerous, ca. 230 per capitulum, ca. 4× more staminate than pistillate; floral bracts obovate to narrowly elliptical or rarely obtrullate, hyaline to castaneous distally, navicular, 3 − 5 mm long, abaxially pilose distally, margin ciliate with long trichomes toward the acuminate apex. Staminate flowers ca. 4.5 mm long; pedicel short ca. 0.5 mm long, glabrous; sepals fused up to the median portion, obovate, cream-colored to castaneous distally, ca. 3.5 mm long, the abaxial surface pilose distally, densely ciliate toward the obtuse to acuminate apex; anthophore fleshy, elongate ca. 1 mm long; corolla fused into a tube, hyaline, membranaceous, ca. 3 mm long; stamens ca. 4 mm long, cream-colored; carpellodes 3, papillose. Pistillate flowers ca. 4.5 mm long, pedicel 0.5 − 0.8 mm long; sepals fused at the base, obovate, cream − colored to castaneous distally, ca. 4 mm long, abaxially pilose distally, densely ciliate toward the acuminate to mucronate apex; petals free, obovate, hyaline, ca. 4 mm long, on the abaxial surface pilose distally, densely ciliate toward the obtuse apex; gynoecium 4.5 mm long, stigmatic branches bifid at the apex, two times longer than nectariferous branches, staminodes scale-like. Fruit a loculicidal capsule released by the recurved sepals. Seed not seen.

Etymology: —The epithet “ calvescens ” is related to the species indument of leaves, spathes, and scapes with very short adpressed trichomes to usually glabrescent or completely glabrous.

Distribution, Habitat, and Conservation: Populations of Paepalanthus calvescens were observed growing in the shade of a forest over sandy-rocky, quartzitic soils at an altitude of ca. 1250 m. The species is restricted to the rural area of Vargem Alta municipality, close to the border with Pedra Azul State Park in Domingos Martins municipality. The populations of P. calvescens are not enclosed in any conservation unit, but grow along the roadside of an area undergoing intense mining and pasture activities ( Fig 1 A ). The species could be considered endangered based on the IUCN (2011) criteria, EN: B1ab (i,ii,iii,iv).

Additional specimens examined: BRAZIL. Espírito Santo: Vargem Alta , 20.IV.2011, A. P. Fontana & L. Kollmann 7319 ( MBML) ; 24.IX.2016, L. E. F. Silva et al. 48 ( R) ; 24.IX.2016, L. E. F. Silva et al. 49 ( RB) ; 11.IV.2017, L. E. F. Silva & I. M. Rollim 116 ( RB) .

Comments: A superficial morphological analysis could place Paepalanthus calvescens into P. ser. Paepalanthus Ruhland (1903: 123) due to its trimerous flowers arranged in a single capitulum sustained by scapes arranged in a rosette with a short stem. This placement is here avoided, as the main cohort of scapes of the new species is not axillary, but terminal, developing in a different growing form. The new shoots may arise from the rhizome or from the dying rosette itself, directly under the inflorescence ( Fig 2 A ), forming dense clumps through vegetative reproduction ( Fig. 1 B, C ). Additionally, P. ser. Paepalanthus is regarded as polyphyletic ( Andrade et al. 2010, Trovó et al. 2013), and until a more comprehensive and stable classification system is available, P. calvescens remain assigned only to P. subg. Paepalanthus Ruhland (1903: 121) . A detailed comparison with P. capixaba , the morphologically most similar species, and other similar species is presented below.

The new species is morphologically and geographically closer to Paepalanthus capixaba , but easily differentiated by its leaves, spathes, and scapes with very short adpressed trichomes along the blade and rarely long trichomes close to the base margin to usually glabrescent or completely glabrous. Additionally, P. calvescens is differentiated from P. capixaba by its more discoid to hemispherical capitula (vs. hemispherical to spherical), castaneous involucral bracts (vs. cream colored to golden), obovate to narrowly elliptical or rarely obtrullate floral bracts with acuminate apex (vs. oblong floral bract with obtuse to acuminate apex), larger staminate and pistillate flowers with ca. 4.5 mm long (vs. ca. 3.5 mm long), sepals of staminate flowers fused up to the median portion (vs. sepals fused only at the base), sepals of staminate flowers with obtuse to acuminate apex (vs. mucronate), sepals of pistillate flowers with acuminate to mucronate apex (vs. mucronate). The pilosity of the perianth whorls of both species is also slightly different on the abaxial surface of the sepals and petals, a condition that may vary according to the developmental stage of the flower.

When describing Paepalanthus capixaba, Trovó et al. (2016) commented on the specimen A.P. Fontana 7319 (MBML) as not fitting the species circumscription, mainly because of its mostly glabrous leaves, spathes, and scapes. Trovó et al. (2016) hypothesized that such variation could be related to the shady habitat of the specimen. After fieldtrips to the type locality, some individuals of P. capixaba were found growing in shaded habitats and retaining the typical densely sericeous pilosity of the species. It is also relevant that, although P. capixaba and P. calvescens occur in the same municipality, they should not be considered sympatric. Paepalanthus capixaba populations were seen mostly in open areas of sandy soils closer to the urban zone of Vargem Alta at an altitude of ca. 700 m, while P. calvescens is distributed northwards, growing in the shade of a forest over a sandy-rocky soil at an altitude of ca. 1250m. The specimen A.P. Fontana 7319 (MBML), collected north of Vargem Alta Municipality is here assigned to P. calvescens .

Paepalanthus spathulatus Körnicke (1863: 389) , a species mostly distributed in the Espinhaço Range, in Minas Gerais and Bahia states is also morphologically similar to P. calvescens . The new species described here is however differentiated by its more gracile habit 23.7 − 38.5 cm long (vs. robust habit with 30.0 − 63.0 cm long), shorter stem ca. 2 − 3 cm long (vs. longer stem ca. 6 − 10 cm long), leaf apex acute (vs. acuminate apex), scapes 12.8 − 29.2 cm long (vs. 16.0 − 62.0 cm long), discoid to hemispherical capitula (vs. spherical), ovate to elliptical involucral bracts with obtuse to mucronate apex (vs. ovate to lanceolate involucral bracts with obtuse or acuminate to cuspidate apex), floral bracts hyaline to castaneous distally (vs. greenish), sepals of the staminate flower fused up to the median portion, obovate with obtuse to acuminate apex (vs. free, lanceolate to spathulate with apex rounded to truncate), sepals of the pistillate flowers obovate with acuminate to mucronate apex (vs. oblong − ovate to spathulate with. acute apex), petals of the pistillate obovate (vs. spathulate − oblong).

Paepalanthus calvescens also shares morphological similarities with P. calvus Körnicke (1863: 381) , a species mainly distributed in the Mantiqueira Range in Minas Gerais and São Paulo states. Paepalanthus calvescens can be differentiated from P. calvus by its longer and wider leaves 13.7 − 30.3 × 1.0– 2.4 cm (vs. 4.7–10 × 0.4 − 0.8 cm), shorter spathes 5.1 − 10.9 cm long with acute apex (vs. 18.4 − 35 cm long with acuminate apex), usually shorter scapes 12.8 − 29.2 cm long (vs. 15 − 46 cm long), capitula discoid to hemispherical (vs. hemispherical to spherical), involucral bracts with obtuse to mucronate apex (vs. acute), hyaline to castaneous distally floral bracts with acuminate apex (vs. greenish to blackish distally floral bracts with obtuse apex), cream-colored to castaneous distally sepals of staminate flowers fused up to the median portion (vs. greenish to blackish distally sepals of staminate flowers fused only at the base), sepals of the pistillate flowers cream − colored to castaneous distally with acuminate to mucronate apex (vs. greenish to blackish distally with acute apex), petals of the pistillate flowers obovate (vs. oblong).

Figures

FIGURE 1. Paepalanthus calvescens Silva & Trovó. A. Habitat detail. B. Population. C. Clump detail. D. Habit detail. E. Rosette detail. F. Scapes insertion. G, H. Capitulum detail (Photos: I.M. Rollim).

FIGURE 2. Paepalanthus calvescens Silva & Trovó. A. Rosette without leaves, exposing the terminal inflorescence and the lateral shoot. B. Leaf. C. Leaf apex. D. Leaf margin. E. Scape detail. F. Spathe and scape detail. G. Spathe detail. H. and I. Involucral bract, abaxial surface. J. and K. Floral bract, abaxial surface. L. Staminate flower. M. Staminate flower with sepals removed. N. Staminate flower with sepals and petals removed. O. Sepals of pistillate flower. P. Pistillate flower with sepals removed and corolla opened (Photos: I.M. Rollim).