Paepalanthus ferrugineus Andrino & Echtern., 2021

Echternacht, Livia, Watanabe, Maurício Takashi Coutinho & Andrino, Caroline Oliveira, 2021, Novelties from the Serra Nova State Park (Minas Gerais, Brazil): two new endemic species of Eriocaulaceae, Phytotaxa 505 (2), pp. 187-200 : 188-194

Paepalanthus ferrugineus Andrino & Echtern. , sp. nov. ( Figs. 1 , 2 , 3 ).

Type:— BRAZIL. Minas Gerais: Rio Pardo de Minas, Parque Estadual da Serra Nova. Alto da serra, passando pela estrada até Gerais Santana , 1257 m elev., 15 o 40’36” S 42 o 48’49” W, 19 April 2014, L . Echternacht , T. V . Bastos , M. S . Freitas & A. P. L . Werlang 2415 (holotype OUPR! [29438], isotypes B!, HUFU!, NY!, P!, RB! SPF!) .

Diagnosis:— The new species is similar to Paepalanthus bombacinus ( Silveira 1928: 83) , P. regelianus Körnicke (1963: 386) , P. regalis Körnicke (1963: 393) , and P. barbulatus Herzog (1924: 83) , sharing the robust rhizomatous habit, with basal leaf rosettes and scapes two to three times longer than the leaves. It is distinguished from these species by the rust-colored involucral bracts (vs. brown), surpassing the floral disc in early mature capitula (vs. not surpassing the floral disc), and tufted adaxially (vs. glabrous), together with the petals of pistillate flowers distally brown (vs. cream to straw-colored).

Perennial herbs, terrestrial, 15–60 cm tall. Roots ca. 1 mm diam. Rhizome sub-horizontal to erect, 3–10 cm long, branched or not. Basal rosettes of leaves solitary or branching at ground level. Leaves 6–20 × 0.5–1 cm, lanceolate, chartaceous, striate abaxially with prominent veins, margins thickened, apex acute to acuminate; abaxially glabrous, adaxially pilose, pubescent to glabrous, margin ciliate to glabrous; hairs simple, patent, of two lengths, short 0.1–0.3 mm and long 1–5 mm long. Spathes 6–20 cm long, as long as the leaves or exceeding them by 1–2 cm, opening obliquely, 3–20 mm long, acute to acuminate, chartaceous, pilose to glabrescent; hairs sparse, denser at the apex, margin ciliate, hairs similar to those on the leaves, dehiscent, base bulbous, persistent. Scapes axilar, 18–55 cm long, 3–4-costate, pilose to pubescent; hairs simple, ascending, 1–6 mm long, dehiscent, base bulbous, persistent. Capitula 11–18 mm in diameter, hemispherical. Involucral bracts in (3–)5–8 series, brown, commonly with a reddish to orange tinge, darker at apex, those of the external series ovate to ovate-triangular, 3–5 × 1–1.5 mm; those of the internal series ranging from ovate-triangular to narrow triangular, 4–8 × 1.5–3 mm, surpassing the floral disc 1–2 mm in early mature capitula, apex acute to attenuate; abaxially tomentose, adaxially tufted distally, ciliate, hairs simple, appressed, 0.3–2 mm long, cilia longer on the internal series. Floral bracts light to dark brown, darker at the apex, grading to straw-colored toward the base, 2.9–5.7 (–7.2) × 0.2–0.7 mm, often surpassing the flowers by 0.3–0.5 (–0.6) mm, dark apices often visible on the surface of the capitulum, more or less linear or broadest near the middle, apex obtuse to acute; hairs similar to those on the involucral bracts, apical tuft (0.2–) 0.4–1 mm long, decurrent along margins ca. 1 mm. Flowers 3-merous, actinomorphic, 2.5–4 mm long including the pedicel, membranaceous, more than 200 per capitulum, forming cycles of staminate flowers intercalated by cycles of pistillate ones; pedicel brown, ca. 0.5 mm long, densely pilose with simple hairs ca. 2 mm long. Staminate flowers with sepals dark to light brown, lighter toward the cream-colored base, 2–3 mm long, free, concave, narrow obovate, apex obtuse to acute, abaxially glabrous, adaxially tufted at apex, ciliate, hairs simple, decurrent along margins ca. 0.5 mm, dehiscent; anthophore ca. 0.5 mm long; petals light brown to brown, with a greenish tinge, ca. 2 mm long, fused, tubular, truncate, with six short lobes ca. 0.2 mm long, alternate and opposite to the stamens, involute after anthesis, ciliate; stamens 2.5–3 mm long, epipetalous ca. 0.6 mm long, cream-colored to yellowish, introrse, exserted; pistillodes brown, ca. 0.5 mm long, apex cream-colored, fimbriate. Pistillate flowers with sepals straw-colored from base to middle, dark brown at apex, 2–3 mm long, fused at base, concave, oblong, apex obtuse, tufted at the apex on both surfaces, hairs simple, decurrent along margins ca. 0.5 cm long, dehiscent, thickening during fruit maturation, hygroscopic; petals cream-colored, brown at apex, 2–2.5 mm long, free, oblong to narrow obovate, pilose as the sepals; gynoecium 2.5–3 mm long; ovary ca. 0.7 mm long, style column ca. 0.2 mm long, nectariferous portion brown, 0.5–0.7 mm long, fimbriate at apex, stigmatic portion brown, shortly bifid, 1.5–2 mm long, exserted. Seed 0.6 × 0.3 mm, ellipsoid, reddish-brown, reticulate, with longitudinal striations prominent.

Etymology:— The epithet “ ferrugineus ”, Latin for rusty, refers to the distinctive rust-colored involucral bracts of this species.

Flowering:— It was collected with flowers and fruit in March and April, suggesting a flowering period at the beginning of the dry season.

Distribution and habitat:— The species is endemic to the SNSP, forming large populations of hundreds of individuals, mainly on the high plateaus of the Serra Nova, with records ranging from 850 to 1300 m elev. It grows on open, quartzitic Campos Rupestres, among herbaceous to shrubby vegetation, growing over white to grey, sandy to gravelly soil.

Conservation status:— The species is known from a single locality, but forms large populations within a restricteduse protected area, on its more isolated and conserved highlands. In spite of these circumstances, disturbances occur related to fire, cattle grazing, and road construction, the responsible governmental agencies often lack resources for maintenance and surveillance, and the conservation of habitat quality cannot be taken for granted. Based on the IUCN Red List guidelines and criteria, it is assessed as Critically Endangered, considering its EOO of 57 km 2 (B1), its AOO of 5 km 2 (B2), one known location (Ba), and declining quality of habitat (Bb).

Notes and taxonomic affinities:— Paepalanthus ferrugineus is very similar to species of P. subg. Xeractis ( Körnicke 1863: 336) , a lineage endemic to the campos rupestres of Minas Gerais ( Andrade et al. 2010, Trovó et al. 2013, Andrino et al. 2021). The new taxon shares with the species of this subgenus the following characters: adaxially pilose involucral bracts surpassing the floral disc, pilose petals of pistillate flowers, and tufted involucral bracts and sepals, with decurrent hairs along margins ( Hensold 1988). The synapomorphy of P. subg. Xeractis is the corolla of staminate flowers pilose adaxially, but P. ferrugineus has ciliate petals, glabrous adaxially. Thus, despite these morphological resemblances, the listed differences led us to discard this species as a member of Paepalanthus subg. Xeractis .

A group of about 20 species included in Paepalanthus ser. Paepalanthus have morphological characteristics similar to P. ferrugineus , with many of them closely related phylogenetically (Clade Q, Andrino et al. 2021), while others have not yet been tested. They are robust species, more than 30 cm tall, with short aerial stems and lignified subterranean stems, usually vertical, leaves flat, persistent, lanceolate, disposed in rosettes, numerous (15–30) scapes per individual and usually twice to thrice as long as the leaves. Within this group, P. ferrugineus is morphologically similar to P. bombacinus , to P. regelianus , and to P. regalis , all from the Espinhaço Range in Minas Gerais state. Another similar species is P. barbulatus , from the Espinhaço Range in Bahia state. No sympatric species belongs to this group, although the area is still poorly sampled. Paepalanthus ferrugineus can be distinguished from these four taxa by the rust-colored involucral bracts (vs. brown), surpassing the floral disc in early mature capitula (vs. not surpassing the floral disc), and tufted adaxially (vs. glabrous), together with the petals of pistillate flowers distally brown (vs. cream to straw-colored). Leaf indumentum is quite variable among these species, but densely pilose individuals were observed in P. ferrugineus and not in the other species, which tend to be pubescent to glabrous. Paepalanthus ferrugineus has narrower leaves than P. regalis and P. regelianus (0.5–1 vs. 1.1–2.2 cm) and tomentose involucral bracts (vs. pubescent to glabrous). Paepalanthus regalis has a very distinctive feature, bilateral capitula, while the other Paepalanthus have radial capitula. Another differences from these species are detailed in Table 1.

Additional specimens examined (paratypes):— BRAZIL. Minas Gerais, Rio Pardo de Minas, Parque Estadual da Serra Nova. Alto da serra, passando pela estrada até Gerais Santana , 976 m elev., 15 o 46’47” S 42 o 46’15” W, 19 April 2014, L . Echternacht et al. 2414 ( DIAM! HUFU!, HDJF!, MCCA!, OUPR!); alto da serra, passando pela estrada até Gerais Santana , 1244 m elev., 15 o 40’16” S 42 o 48’57” W, 19 April 2014, L . Echternacht et al. 2408 ( HUFU!, OUPR!); topo do Morro do Gerais, 1298 m elev., 15 o 39’42” S 42 o 45’58” W, 22 March 2012, L. A. A . Góes-Neto et al. 697 ( BHCB!); trilha Areial em direção ao açude, 850 m elev., 15 o 39’14” S 42 o 43’53” W, 20 March 2012, M. J. R Rocha et al. 402 ( BHCB!) .

Figures

FIGURE 1. Distribution map of Paepalanthus ferrugineus and Syngonanthus polyaxis in the Serra Nova State Park, Espinhaço Range, Minas Gerais, Brazil. Map I. Topographic map. Map II. Satellite imagery map.

FIGURE 2. Paepalanthus ferrugineus line drawings. A. Habit. B. Scape and capitulum. C. Involucral bract, abaxial surface. D. Floral bract, adaxial surface. E. Staminate flower subtended by floral bract. F. Staminate flower with open corolla. G. Pistillate flower with floral bract. H. Pistillate flower dissected to expose the gynoecium. Illustration by: Klei Souza.

FIGURE 3. Paepalanthus ferrugineus. A–B. Habitat. C. Habit. D–E. Rosette leaf, spathes and scapes showing indumentum variation from glabrous (D) to pilose (E). F–I. Capitula in various stages of development, view from below (F, G), lateral (H) and above (I). Photos by Livia Echternacht.