Nadia Roque (Roquea) from Brazil to accommodate new species multiphyllaries roquea (Roquea multiserialis)

NEWS - Researchers report the results of a morphological, anatomical and phylogenetic study describing Nadia Roque (Roquea Loeuille & Antar gen. nov.), a new genus of Asteraceae from Brazil, to accommodate the new species multiphyllaries roquea (Roquea multiserialis Loeuille & Antar sp. nov.).

Roquea joins a growing list of Asteraceae genera recently described from Brazil, such as Maschalostachys, Lapidia Roque & S.C.Ferreira (2017), Lychnophorella Loeuille (2019), Archidasyphyllum (Cabrera 1959) Ferreira (2019) and Vickia Roque & Sancho (2020).

The first collection of R. multiserialis dates back to 2018 by G. Martinelli during a Bromeliaceae collecting expedition. The area is currently being systematically collected by the efforts of the Centro Nacional da Conservação da Flora and by a group led by the project “Plano de Ação Territorial Espinhaço Mineiro” which aims to publish a book detailing the flora of the area.

R. multiserialis is currently considered endemic to the Serra da Formosa area, in the municipality of Monte Azul, in the northern part of the Espinhaço Mountains, Minas Gerais, Brazil. This species is found only at elevations above 1700 meters in campo rupestre vegetation. It grows among rocks in sandy-rocky soils. It flowers in March-April and fruits in October.

Other species in the habitat include Baccharis platypoda Candolle (1836), Begonia grisea Candolle (1859), Clusia burle-marxii Bittrich (1996), Declieuxia cacuminis Müller Argoviensis (1876), Lippia hederifolia Martius & Schauer (1847), Miconia sclerophylla Triana (1872), Mimosa aurivillus Martius (1838), and Symphyopappus cuneatus (Candolle 1836).

R. multiserialis is currently only known from four collections and has a very restricted distribution, a common pattern seen in microendemic species in the Campos Rupestres. The Serra da Formosa has experienced threats caused by humans, including fires, quartzite mining and road construction for wind turbine generator installations.

If these threats continue within their potential range, they could have a negative impact on the species, leading to habitat degradation and decline. Considering the species' limited distribution, potential threats, and AOO value, the researchers propose the status of R. multiserialis as Critically Endangered.

DESCRIPTION

Roquea multiserialis Loeuille & Antar sp. nov., adhuc unica.

Treelet or shrub up to 2 m tall. Stems moderately branched, greyish, blackish towards base, pubescent, indumentum composed of long-stalked stellate trichomes, sometimes with forked arms or geminate or short-stalked and swollen stellate trichomes.

Leaves shortly petiolate, 3–5 mm long, leaf sheath semi-amplexicaul, 2.2–4.1 × 2.9–5 mm, adaxially densely white pilose (unbranched long trichomes); blade rhombic, wide obovate, rarely wide elliptic, 2.6–4.9 × 1.4–2.7 cm, venation eucamptodromous, midrib thick and flattened, furrowed, prominent abaxially, sunken adaxially, including secondary veins, chartaceous to subcoriaceous, conspicuously discoloured, adaxial surface green, dark green or nearly black in sicco, glabrescent with sparse short-stalked swollen stellate trichomes, tomentose in the midrib, especially near the base, glandular-punctate, abaxial surface greyish lanate, older leaves dark greyish, lanate, indumentum composed of dense short-stalked swollen stellate trichomes along midrib and venation and sparse darker long-stalked stellate trichomes in stomatal crypts, sometimes with forked arms or geminate, margin slightly thickened, entire or sinuate to crenate, especially near apex, apex obtuse or acute, sometimes retuse or acuminate, base attenuate or cuneate.

Inflorescence axillary, capitula organised in a dense corymb; flowering branch 7.7–20.5 cm long, cylindrical or slightly flattened and four-angled, mostly near base of capitula, greyish, sometimes blackish, pubescent, indumentum composed of stellate trichomes with long- or short-stalked trichomes, leaf-like bracts 0.9–2.9 × 0.5–1.4 cm.

Capitula 3–6 per corymb, pedunculate, associated to 1–2 leafy spatulate tomentose subinvolucral bract erect or slightly conduplicate towards apex, peduncle 1.4–3.2 cm long, flattened, costate, greyish, sometimes blackish, with similar indumentum as branches; involucre 9.5–13.1 mm tall, 12–18.5 mm in diam., campanulate; phyllaries imbricate, 7–9-seriate, densely light greyish to ochraceous, indumentum of short-stalked stellate and unbranched trichomes, apex dark brown and sparsely tomentose, outer phyllaries ovate to elliptic, 3.4–4.3 × 1.6–2.1 mm, apex acute and recurved, inner phyllaries elliptic to narrowly oblanceolate, 4.8–6.7 × 1.1–1.9 mm long, acute to acuminate and straight to slightly recurved; receptacle fimbrillate, fimbria up to 0.5 mm.

Florets 130–150 per capitulum; corolla lilac to pale pink, usually actinomorphic but sometimes asymmetric due to a higher number of lobes and size variation of sinuses, corolla tube 4.5–5.8 × 0.3–0.6 mm, glabrous, sparsely glandular-punctate, corolla lobes 5(–8), 3.2–4.1 × 0.3–0.5 mm, glabrous or sparsely pubescent, apex acute, densely villous; anthers 5(–8), purple, apical anther appendage triangular, anther base calcarate and tailed; style lacking a basal node, style shaft 8.1– 8.9 mm long, whitish to lilac, glabrous throughout except for pubescence upper ca. 1.5–2 mm beneath style-arms, style-arms 1.9–2.5 mm long.

Cypsela prismatic, 3.2–4.1 × 0.7–1.1 mm, 10-ribbed, brownish usually with darker extremities, glabrous; carpopodium inconspicuous; pappus setae biseriate, light stramineous, paleaceous, outer series setae 0.9–1.1 mm long, of unequal sizes, slightly fused at base or free, serrulate, sometimes twisted, persistent, apex erose, inner series setae 3.5–4.4 mm, free, slightly serrulate, twisted, deciduous, apex acute.

Original research

Benoît Loeuille, Roberto Baptista Pereira Almeida, Carolina M. Siniscalchi, Makeli G. Lusa & Guilherme Medeiros Antar (2024). Roquea, a new genus of Lychnophorinae (Vernonieae, Asteraceae) from Brazil and its phylogenetic placement. Phytotaxa 675 (2): 097–114, DOI:10.11646/phytotaxa.675.2.1

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