Calea repanda V.R.Bueno, Gostel & G.Heiden, 2022

Bueno, Vinicius R., Gostel, Morgan R. & Heiden, Gustavo, 2022, Calea repanda (Asteraceae: Neurolaeneae), a new species and novel characters for the taxonomy of the genus, Phytotaxa 544 (3), pp. 280-288 : 283-285

Calea repanda V.R.Bueno, Gostel & G.Heiden , sp. nov. ( Fig.2 )

Type:— BRASIL. Minas Gerais, Rio Pardo de Minas, Serra Nova , sítio 25, ponto 2, 23 June 2017, A. C . Sevilha 7016 (holotype: CEN!) .

Calea repanda is morphologically similar to C. diamantinensis and C. gentianoides ; however, it can be distinguished by the leaves with repand margins (vs. entire margins), capitula radiate (vs. discoid), involucre 12.2–12.7 mm × 10.6–12 mm (vs. 5.5–9.4 mm × 2.7–5.2 mm), capitulum with holopaleaceous receptacle (vs. oligopaleaceous or epaleaceous, respectively), disc florets 30–40 (vs. 3–9), and pappus scales 7–10 (vs. 15–20).

Plants herbaceous, up to 0.6 m tall. Stems castaneous, cylindrical, striate, glabrous to sparse pilose, internodes 11.5–15 mm long. Leaves decussate, petiole 1.3–1.5 mm long; blades 1.37–3.31 × 0.59–2.1 cm, wide oblong to wide elliptic, often narrow oblong to elliptic, base rounded, apex obtuse, venation paralellodromous, margins repand, revolute, abaxial surface glabrous to sparsely pilose, rarely pilose, veins glabrous or hispidulous, glands absent, adaxial surface glabrous with margin scabrid, glands absent, coriaceous, discolorous, abaxial surface olivaceous, adaxial surface dark green. Capitula arranged in pairs, terminal; peduncle 0.45–0.7 cm long, hirtellous to hirsute, glandularpunctate. Capitulum heterogamous, radiate; involucre 12.2–12.7 × 10.6–12 mm, campanulate to broadly cylindrical. Phyllaries 6-seriate, conspicuously striate, margins entire, hyaline, flat; outermost series of phyllaries scarious with apex foliaceous, olivaceous with base yellowish green, first series 5.5–5.6 × 3.4–4 mm, broadly oblong or ovate, apex obtuse, sparsely hirsute to sparsely pilose, sparsely glandular-punctate in apex, 6–8-striate; second series 5.3 × 3.9 mm, ovate, apex obtuse, pilose to densely pilose, sparsely glandular-punctate in apex, 8-striate; innermost series scarious, glabrous, pale yellow to green, third series 5.5 × 3.7 mm, ovate, apex rounded, 9–12-striate; fourth series 5.4 × 5 mm, very broadly ovate, apex rounded, 15–18-striate; fifth series 9.6–10.1 × 4.6–4.9 mm, narrowly ovate, apex rounded, 14–15-striate; sixth series 10.4–10.9 × 3.7–4.3 mm, narrowly oblong to lanceolate, apex rounded, 10–12- striate; receptacle flat, holopaleaceous, paleae 8.2–9.6 mm long, narrowly elliptical, concave, apex acuminate or attenuate, light yellow. Ray florets 8–10, pistillate, corolla 13.4–13.8 mm long, liguliform, tube 2.9–3.3 mm long, limb 10.1–10.5 × 2.8–3.8 mm, oblanceolate, apex 3-lobed, 5-veined, abaxial surface glandular-punctate, adaxial surface glabrous, yellow; style arms 1.0– 1.1 mm long, linear, yellow. Disc florets 30–40, bisexual, corolla 5–5.4 mm long, tubular, tube 1.3–1.6 mm long, lobes 0.8–1.2 mm long, glabrous, yellow; anthers 2.4–2.5 mm long, light yellow, apical anther appendages trullate; style arms 0.8–1.1 mm long, linear, yellow. Cypselae 3.0– 3.2 mm long, black, prismatic, ray cypselae 3-angled, disc cypselae 4-angled, glabrous to pilose, ribs densely pilose; pappus 7–10, bitypic, scales bilength (1–2 distinctly longer) or polylength, free, uniseriate, shorter scales (1.1–) 2.4–3.5 mm long, medium scales 3–3.4 mm long (exclusively present when polylength), longer scales 3.1–4.3 mm long, narrow elliptic to lanceolate, apex long acuminate, margins entire, erose.

Distribution and Habitat:— Calea repanda is a stenoendemic species that occurs exclusively in one municipality in the north of Minas Gerais state: Rio Pardo de Minas ( Fig. 1 ). This new species grows in areas of Campo Rupestre (rocky outcrops tropical grasslands) in elevations around 800 m.

Informal Conservation Status:—Critically Endangered (B1; B2a; C2 i, ii; D). Calea repanda is represented by one single specimen. A. C. Sevilha (the collector) is one of the coordinators of the Bem Diverso Project ( Sevilha et al. 2022) and tried to find the species in the surroundings during other trips to the field, but he failed (pers. comm.). The species was collected in an area where the Bem Diverso Project is being developed, which aims to combine sustainable development with nature conservation (Sevilha et. al. 2022), but it is not a protected area. According to the IUCN (2019) criteria, this new species meets the following requirements: the criteria B1 (less than 100 km ² of extent of occurrence), B2 (less than 10 km ² of area of occupancy) and the condition A of criterion B (because it has one known location); criterion C, conditions i and ii of C2, and the criterion D are applied for having only one known mature adult individual.

Etymology:—The epithet “repanda” refers to the repand margins leaf, a morphological trait not found in any other species of Calea from Brazil.

Phenology:—The holotype was collected with florets and fruits in June.

Taxonomic comments:—The unbranched stem, heads arranged in pairs, and especially the repand margin leaf distinguishes this species and is likely why this specimen remained unidentified since its collection. The repand margin is a unique trait in Brazilian Calea and the capitula arranged in pairs are also quite uncommon. Despite the importance of capitulescence in differentiation of sections of Calea ( Bueno et al. 2021) , the reduced capitulescence of C. repanda did not provide any hint in which section it would be likely placed.

The morphological feature from the specimen supports its recognition as a new species. The analyses of the pappus, predominantly longer than the cypselae, corroborates that the new species belongs to C. sect. Calea . The two more widespread species of this section in Brazil are C. pinnatifida (Brown 1818: 109) Lessing (1830: 158) and C. lantanoides Gardner (1848: 416) . Calea repanda is easily distinguishable from these two species by the habit herbaceous 0.6 m tall (vs. shrubby 1–5 m), petiole 1.3–1.5 mm long (vs. 3.5–9 mm), leaf margin repand (vs. pinnatifid or serrate), capitula arranged in pairs (vs. cymose umbelliform), involucre wide 10.6–12 mm (vs. 3.4–8 mm), corolla of the ray florets 13.4–13.8 mm (vs. 7–11.2 mm, absent in C. lantanoides ), disc florets 30–40 (vs. 7–21), and pappus scales 7–10 (vs. 16–43).

Calea repanda is morphologically similar to C. gentianoides Candolle (1836: 672) and C. diamantinensis Silva & Nakajima (2020: 200) ; these three species form a likely group placed in C. sect. Calea . The C. gentianoides group is characterized by the herbaceous habit (uncommon in this section), elliptical to oblong leaves, capitulescences with few capitula, and pappus 2.5–5 mm long. Due to the unusual herbaceous habit in the section, the reduced number of capitula in the capitulescence, and because two of the three species have either epaleaceous or oligopaleaceous receptacles (a putative derived character in Calea ), we suspect that the C. gentianoides group probably has diverged recently within C. sect. Calea .

Calea repanda can be distinguished from the remaining species of the C. gentianoides group ( C. diamantinensis and C. repanda ) by the venation paralellodromous (vs. eucamptodromous or acrodromous), margin repand (vs. entire), capitulum radiate (vs. discoid), involucre 12.2–12.7 mm × 10.6–12 mm (vs. 5.5–9.4 mm × 2.7–5.2 mm), receptacle holopaleaceous (vs. oligopaleaceous or epaleaceous), disc florets 30–40 (vs. 3–9), and pappus scales 7–10 (vs. 15– 20).

Regarding the new terminology proposed to describe the proportion of paleae compared to disc florets on capitulum receptacles ( Tab. 1 ), we expect this terminology will be applicable to species of all sections of Calea (Pruski 1998) . From the five sections, only C. sect. Haplocalea Pruski (1998: 683–684) unanimously have holopaleaceous species. From the other sections, at least 18 species of Calea (ca. 11% of the genus) have a smaller proportion of paleae compared to disc florets. Meanwhile, leastwise 17 species (ca. 11% of the genus) have an epaleaceous receptacle.

Figures

FIGURE 1. Distribution of Calea repanda (Neurolaeneae, Asteraceae) in Brazil. MG—Minas Gerais State, BA—Bahia State, ES— Espírito Santo State, RJ—Rio de Janeiro State.

FIGURE 2. Calea repanda sp. nov. (Neurolaeneae,Asteraceae) A. Flowering branch. B. Leaf, abaxial surface. C. Capitula with ray florets removed to show involucre, paleae and disc florets arrangements. D. First series of phyllaries. E. Second series of phyllaries. F. Third series of phyllaries. G. Fourth series of phyllaries. H. Fifth series of phyllaries. I. Sixth series of phyllaries. J. Ray floret. K. Disc floret with bilength pappus scales. L. Cypsela with polylength pappus scales.A–L drawn from A. C. Sevilha 7016 (CEN);A–L: millimeter scale. Illustration by Débora Dalzotto.