Actinocephalus pachyphyllus: re-establishment ... - Springer Link

KEW BULLETIN VOL. 67: 25 Y 31 (2012)

ISSN: 0075-5974 (print) ISSN: 1874-933X (electronic)

Actinocephalus pachyphyllus: re-establishment, redefinition, and a new combination in Eriocaulaceae from Brazil Marcelo Trovó1,2, Fabiane Nepomuceno Costa3 & Lívia Echternacht1,4

Summary. We report the rediscovery of Paepalanthus macrocephalus var. pachyphyllus, an obscure taxon known exc-

lusively from the type specimen. We formally re-establish the species Paepalanthus pachyphyllus and propose its combination within Actinocephalus. The species is redefined and illustrated. Actinocephalus pachyphyllus F. N. Costa, Trovó & Echtern. (Eriocaulaceae, Paepalanthoideae) is distinguished from closely related species by possessing cylindrical to canaliculate linear leaves, covered by long trichomes at the base, with a round to obtuse apex, and short paraclades bearing a single scape. The species is endemic to the Espinhaço Range in Minas Gerais. We compare it with Paepalanthus glareosus (Bong.) Körn. and P. trichopeplus Silveira, the most morphologically similar species. Comments on morphological variation, habitat, geographic distribution, conservation status as well as line drawings, photos, and a distribution map are provided. Key Words. endemism, Espinhaço Range, IUCN Red List, Minas Gerais, Paepalanthoideae.

Introduction Within the genus Eriocaulon (Eriocaulaceae), Bongard (1831) created an informal group ‘Umbellata’ comprising nine species with trimerous flowers and scapes arranged in umbel-shaped inflorescences. Körnicke (1863) included most of these species within Paepalanthus subgen. Actinocephalus Körn., which Sano (2004) raised to generic status. The group was defined by possessing paraclades (ramifications) composed of capitula arranged as a spherical umbel, and simple stigmas. Recently, Costa (2005) pointed out that the distinction between Actinocephalus and Paepalanthus subsect. Aphorocaulon Ruhland is meaningless, as the spherical umbel is not sufficient to distinguish them. Species of Actinocephalus and P. subsect. Aphorocaulon emerge as a consistent clade in recent phylogenetic studies (Andrade et al. 2010). In this sense, both have the same diagnostic features and should be merged. The group is now recognised by possessing paraclades and simple stigmas (Costa 2005). Most taxonomic research dealing with Actinocephalus is restricted to descriptions of new taxa. Silveira (1928) collected and described 20 new species from Minas

Gerais. Moldenke (1937, 1946) provided two new names, Paepalanthus coutoensis Moldenke (= A. coutoensis (Moldenke) Sano) and P. herzogii Moldenke (= A. herzogii (Moldenke) Sano) for the later homonyms P. barbulatus Silveira and P. ruhlandii Herzog. Sano (1998) described P. humilis Sano (= A. herzogii var. humilis (Sano) Sano) from Bahia. Costa (2006) published three new species of Actinocephalus from the Espinhaço Range. Trovó & Costa (2009) described A. koernickeanus, endemic to the vicinity of Serro in Minas Gerais. Finally, Trovó & Sano (2010) described A. verae, sympatric to the latter species. The genus comprises 33 species; an additional 16 species, belonging to Paepalanthus subsect. Aphorocaulon, will be transferred to Actinocephalus (see Costa 2005). Most of these species occur in the campos rupestres, a grass dominated assemblage occurring on rocky soils above 900 m, in eastern Brazil. The diversity is concentrated in elevated areas of the Espinhaço Range in Minas Gerais and Bahia; a few species are found in central Brazil in savannas, or on the Brazilian coastline on sand dunes (Costa 2005; Giulietti & Hensold 1990; Sano 2004). The habitats occupied by

Accepted for publication January 2012. 1 Laboratório de Sistemática Vegetal, Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, CEP 05508-900, São Paulo, BrazilR 2 Departamento de Botânica, Instituto de Biologia, Universidade Federal do Rio de Janeiro, CEP 21941-590, Rio de Janeiro, Rio de Janeiro, Brazil. e-mail: [email protected] 3 Departamento de Ciências Biológicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Campus JK, Rodovia MG 367, 5.000, CEP 39100-000, Diamantina, Minas Gerais, Brazil. e-mail: [email protected] 4 UMR 7207 CNRS MNHN UPMC, Centre de Recherche en Paléobiodiversité et Paléoenvironnements, MNHN, 57 rue Cuvier, CC48, F75005, Paris, France. e-mail: [email protected]

© The Board of Trustees of the Royal Botanic Gardens, Kew, 2012

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Actinocephalus are usually dry, rocky-sandy soils dominated by grass assemblages. As these habitats are, in general, restricted to mountaintops, most of the species are narrowly distributed, restricted to a single mountain or a few adjacent mountains. (Costa et al. 2008; Giulietti et al. 2005). As a consequence, some species are known exclusively from a single historical collection, resulting in a confusing taxonomy and nomenclature (Echternacht et al. 2010). During recent field trips to the Espinhaço Range, we recollected an obscure Paepalanthus Mart. taxon, which was known only from the type collection. Here we re-establish its specific status, propose a new combination within Actinocephalus, provide a detailed description, and make comments on its morphology, distribution, phenology, and conservation status.

Taxonomic treatment Actinocephalus pachyphyllus (Körn.) F. N. Costa, Trovó & Echtern. comb. nov. Type: Brazil, Minas Gerais, 1824, Riedel s.n. (holotype LE!). http://www.ipni.org/urn:lsid:ipni.org:names:77118116-1 Paepalanthus pachyphyllus Körn., Fl. Bras. (Martius) 3 (1): 378 (Körnicke 1863). Paepalanthus macrocephalus var. pachyphyllus Ruhland, in Engler (1903: 171), synon. nov. Perennial herbs, 30 – 59 cm tall; stem short 1 – 3 cm, horizontal rhizome present. Leaves rosulate, cylindrical to canaliculate, erect to patent, linear, 3 – 17 × 0.1 – 0.4 cm, adaxial surface glabrescent, abaxial surface glabrous, apex round to obtuse, young leaves barbate at the apex, glabrescent to ciliate toward the margins, base with dense and long trichomes on both surfaces, senescent leaves glabrous. Paraclades 0.5 – 3 cm, c. 2 – 3.5 mm diam., hairy; paracladial bracts patent, lanceolate, 1 – 4 × 0.1 cm, adaxial surface glabrescent, abaxial surface glabrous, apex acute, base semiamplexicaul, young bracts barbate at the apex. Spathes 3 – 7.5 cm, hairy to glabrescent, with simple and T-shaped, adpressed to patent trichomes, apex acute to lacerate, margins membranaceous. Scapes 1 per paraclade, 28 – 53 cm, densely hairy to glabrescent, with simple and T-shaped trichomes, adpressed to patent. Capitula 8 – 14 mm diam., hemispherical; involucral bracts dark brown, castaneous at the base, hyaline at the margins, elliptic to obovate, c. 3 mm, apex acute to round, adaxial surface glabrous, abaxial surface pubescent at the apex; receptacle hemispheric, pubescent. Flowers 3-merous, c. 200 to 300 per capitulum, c. 5 × more staminate than pistillate flowers; floral bracts light brown to castaneous, lanceolate, c. 3 mm, © The Board of Trustees of the Royal Botanic Gardens, Kew, 2012

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hairy on dorsal surface apex to glabrescent, apex acute, ciliate toward the apex. Staminate flowers c. 4 mm; pedicel c. 1 mm long, with long trichomes; sepals light brown to castaneous, obovate, c. 3 mm, hairy on dorsal surface to glabrescent, apex acute, ciliate toward the apex; corolla hyaline, c. 3 mm; stamens c. 1 mm; pistillodes 3, papillose. Pistillate flowers c. 3 mm, sessile; sepals brown to light brown, navicular, c. 3 mm, hairy to glabrescent on dorsal surface, apex acute, ciliate toward the apex; petals cream to light brown, oblong to obovate, c. 2 mm, hairy on abaxial surfaces, apex acute, ciliate toward the apex; gynoecium c. 3 mm, simple stigmatic branches, c. 2 mm, nectariferous branches papillose, c. 1 mm; staminodes 3, scale-like. Fruit a loculicidal capsule. Figs 1 and 2. DISTRIBUTION. Populations of Actinocephalus pachyphyllus occur in the Espinhaço Range in Minas Gerais, Brazil. Recent collections come from two localities: Joaquim Felício and Fechados (Map 1). It appears that the species has a disjunct distribution; however, further field efforts may reveal a more continuous distribution. SPECIMENS EXAMINED. BRAZIL. Minas Gerais: Fechados, 18°47'55"S, 43°52'12"W, 1261 m, 26 July 2008, Echternacht & Bastos 1882 (BHCB, SPF); Joaquim Felício, Serra do Cabral, 17°42'28"S, 44°17'51"W, 22 July 2008, Echternacht & Bastos 1869 (B, BHCB, SPF); Serra do Cabral, 17°46'03.7"S, 44°17'09.6"W, 1209 m, 10 Dec. 2009, Costa, Quaresma, Araujo, Silva & Andrino 1166 (BHCB, DIA, SPF). HABITAT. In both localities, individuals grow on dry rockysandy quartzite soil intermixed with grasses at over 1100 m. CONSERVATION STATUS. In both localities, large populations of more than 50 individuals were found. In Joaquim Felício, the species occurs within the Serra do Cabral State Park by the roadside. According to criterion B2a (IUCN 2001), the species is considered Endangered. NOTES. Körnicke (1863) described Paepalanthus pachyphyllus Körn. based on a single specimen collected by Riedel in Minas Gerais, Brazil. In the protologue, Körnicke (1863) describes a plant with a short stem, grouped scapes, and stigmatic branches completely fused (= simple stigmas). Ruhland (1903) placed P. pachyphyllus in synonymy with P. macrocephalus (Bong.) Körn., a morphologically variable species, probably representing a conglomerate of species of similar habit, thus a species of confusing taxonomy. Finally, Costa (2005) suggested excluding P. macrocephalus and its varieties from P. subsect. Aphorocaulon. However, neither Ruhland (1903) nor Costa (2005) had examined the type specimen (deposited in LE), basing their conclusions on Körnicke’s (1863) original description. Careful analysis of the type specimen, together with recent collections, demonstrated that the taxon has a distinct paraclade bearing the scapes (Figs 1 and 2). Thus, it belongs to Actinocephalus, deserving species status, as explained below.

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Fig. 1. Actinocephalus pachyphyllus. A habit; B detail of young leaf apex; C floral bract, adaxial surface; D involucral bract, adaxial surface; E staminate flower; F staminate flower with sepals removed; G pistillate flower with one sepal removed; H gynoecium detail; J scape and capitulum detail. All from Echternacht & Bastos 1869. DRAWN BY KLEI SOUSA.


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Fig. 2. Actinocephalus pachyphyllus. A rosette; B paraclade; C capitulum; D habitat. Scale bar = 1 cm.




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Map 1. Map illustrating geographic distribution of Actinocephalus pachyphyllus. Species occurrences are represented by black squares (■). Source: GTOPO − 30 elevation data. © The Board of Trustees of the Royal Botanic Gardens, Kew, 2012

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Actinocephalus pachyphyllus is easily distinguished from other species in the genus. Even at first glance, the persistent long trichomes covering the leaf base are a striking character. Moreover, it can be differentiated by its leaves that are linear, cylindrical to canaliculate, with a round to obtuse apex, and short paraclades bearing a single scape. A. pachyphyllus is morphologically similar to species of Paepalanthus subsect. Aphorocaulon, possessing paraclades arising directly from the rosette and bearing a single or few scapes, such as P. trichopeplus Silveira and P. glareosus (Bong.) Körn. Based on these characteristics, we place A. pachyphyllus within morphological architectural pattern I (of Oriani et al. 2008). Actinocephalus pachyphyllus shares morphological similarities with Paepalanthus glareosus. Both species are perennial herbs consisting of a short rosette of linear leaves with short paraclades (≤ 3 cm) bearing a single or a few long scapes (> 20 cm). Despite these general similarities, both species are easily distinguished. P. glareosus possesses flat deflexed leaves in contrast to the cylindrical to canaliculate, erect to patent leaves of A. pachyphyllus. The leaves in A. pachyphyllus are usually longer (3 – 17 cm vs 1 – 2 cm) with a round apex, not acute as in P. glareosus. Both species also differ in leaf pilosity. A. pachyphyllus has leaves with a glabrous abaxial surface and with a barbate apex in early development, while P. glareosus has leaves with a hairy abaxial surface and glabrous apex in early development. Both species are allopatric, as P. glareosus is restricted to the Diamantina Plateau (Minas Gerais) and the southern and eastern parts of Serra do Cipó. However, as these areas are quite close, and the habitats occupied by both species are similar, further detailed field studies may reveal a sympatric distribution. Paepalanthus trichopeplus, occurring in the Espinhaço Range, is morphologically similar to Actinocephalus pachyphyllus. Both species have erect to patent linear leaves with long trichomes covering the leaf base. Moreover, in both species, the paraclades always bear a single long scape (> 20 cm). A. pachyphyllus is distinguished from P. trichopeplus by its typically longer leaves (3 – 17 cm vs 3 – 6 cm) and by longer scapes (28 – 53 cm vs 23 cm). In addition, individuals of P. trichopeplus have numerous densely arranged leaves, while A. pachyphyllus has scattered leaves. Both species are allopatric, as P. trichopeplus is restricted to the Morro do Breu, north of Serra do Cipó (Minas Gerais).

Acknowledgments We would like to thank Klei Sousa for the line drawings and Tiago Vilaça Bastos for fieldwork facilities. Financial support: F. N. C., Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG); L. E., Fundação de



Amparo à Pesquisa do Estado de São Paulo (FAPESP); M. T. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

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Trovó, M. & Costa, F. N. (2009). Actinocephalus koernickeanus, a new species of Eriocaulaceae from Minas Gerais, Brazil. Novon 19: 256 – 258. ____ & Sano, P. T. (2010). Actinocephalus verae (Eriocaulaceae), a new species from the Brazilian Campos Rupestres. Brittonia 62: 35 – 38.
