Calea breviflora V.R.Bueno & M.S.Silva, 2025

Silva, Mizalene Silva Da, Bueno, Vinicius Resende, Scatigna, André Vito & Marinho, Lucas Cardoso, 2025, Calea breviflora (Asteraceae): a new species endemic to white sand ecosystems of easternmost Amazon, Maranhão, Brazil, Phytotaxa 682 (1), pp. 91-100 : 93-96

Calea breviflora V.R.Bueno & M.S.Silva , sp. nov.

Type:— BRAZIL. Maranhão: Boa Vista do Gurupi , 1°42’6”S, 46°05’41”W, elev. 5 m a.s.l., 11 May 2023 (fl., fr.), M. S. da Silva, A. V. Scatigna, A. L. Garcia & M. Salazar-Ferreira 133 (holotype: SLUI!; isotypes: BHZB!; HUFU!; MAR!; MG!; RB!) ( Figs 1–2 ) .

Diagnosis:— Calea breviflora is morphologically similar to C. caleoides ( Candolle 1838: 294) Robinson (1975: 428) , but is distinguishable by its shorter petiole 0.6–0.7 mm long (vs. 1.3–4.2 mm), second series of phyllaries with apex foliaceous (vs. scarious), 7–14 disc florets per capitulum (vs. 18–20 per capitulum), and cypselae 1.8–3 mm long (vs. 3.25–3.5 mm).

Shrubs erect, branched, 0.7–1.2 m tall. Stems castaneous, cylindrical, striate, densely strigose, eglandular, internodes 1.1–6.7 (–9.6) cm long. Leaves aromatic, scent resembling mint, decussate; petioles 0.9–2.45 mm long; blades chartaceous, green, discolorous, 0.6–3.1 × 0.2–1 (–1.9) cm, lanceolate, sometimes narrowly ovate, rarely ovate, base attenuate, apex acute, venation acrodromous basal, margin entire, strongly revolute; abaxial surface pilose to hirsute, veins densely pilose, densely glandular-punctate, adaxial surface strigilose, eglandular. Capitulescence cymose, branching to 2nd order ramification, 2 secondary stems; peduncle 0.3–2.53 (4.2) cm long, pilose, eglandular. Capitulum heterogamous, radiate, involucre cylindrical, 4.2–6.9 × 4.6–6.95 mm, 6-seriate; phyllaries conspicuously broadly striate, two outermost series scarious with apex foliaceous, olivaceous, obtuse to rounded, margin entire, flat; first series blades 2–3.2 × 1.3–2.4 mm, ovate or broadly oblong, sometimes oblong or very broadly oblong or narrowly ovate or broadly ovate, densely strigose, glandular-punctate, margin ciliate, 3–5-striate; second series blades 2–2.92 (–3.3) × 1.6–2.7 mm, broadly ovate, often ovate, sometimes very broadly ovate, apex sparsely strigose, glandular-punctate, ciliate, 4–7-striate; innermost series scarious, yellowish green to pale yellow, third series blades 2.4–4 × 2.2–3.15 mm, ovate to broadly ovate, apex rounded, sparsely strigose, punctate, ciliate, 5–7-striate; fourth series blades 3.5–5.7 × 2–3.6 mm, narrowly obovate to obovate or narrowly ovate to ovate, rarely broadly ovate, apex rounded, glabrous, ciliate, 5–7-striate; fifth series blades 4.2–5.7 × 1.2–3.6 mm, obovate to narrowly obovate, often broadly oblanceolate to oblanceolate, apex rounded to obtuse, glabrous, ciliate, 6–8-striate; sixth series blades 4.1–5.7 × 1.1–2.6 mm, oblanceolate, apex rounded to obtuse, glabrous, 5–6-striate. Receptacle epaleaceous. Ray florets 3–7, pistillate, corolla liguliform, 3.2–4.3 mm long, tubes 1–1.8 mm long, limbs 2–3.9 × 1.1–1.95 mm, broadly oblanceolate to oblong, apex 3–4-lobulate, 2–5-veined, yellow, abaxial surface densely glandular-punctate, adaxial surface glabrous; style arms 0.8–1 mm long, yellow. Disc florets 7–14, bisexual, corolla tubulous, 2.45–3 (–4.1) mm long, tubes 0.6–1 mm long, lobes 0.7–1 mm long, yellow, sparsely glandular-punctate; anthers 1–1.2 mm long, yellow, apical anther appendages ovate; style arms 0.8–1 mm long, linear, yellow. Cypselae 1.8–3 mm long, black, cylindric, glabrous to sparsely strigillose in apex, ribs glabrous to sparsely strigillose in apex, ray cypselae 3-angled, disc cypselae 4-angled; pappus 12–14 scales, monotypic, same length, free, uniseriate, scales 1–1.3 mm long, oblong or oblanceolate, apex obtuse, margins entire, erose.

Additional specimens examined (paratypes):— BRAZIL. Maranhão: Boa Vista do Gurupi , 1°41’59”S, 46°05’47”W, 5 m a.s.l., 11 May 2023 (fl., fr.), M. S. da Silva et al. 149 ( SLUI!) ; ibid. 1°40’57”S, 46°05’49”W, 5 m a.s.l., 15 October 2023 (fl., fr.), M. S. da Silva et al. 321 ( HUFU!, SLUI!, TEPB!). Carutapera, 1°32’15”S, 46°06’48”W, 5 m a.s.l., 10 May 2023 (fl., fr.), M. S. da Silva et al. 128 ( INPA!, SLUI!) ; ibid. 1°33’16.0”S, 46°05’44.0”W, 5 m a.s.l., 14 October 2023 (fl., fr.), M. S. da Silva et al. 279 ( CEN!, SLUI!, UB!). Mun. Carutapera, 01°33’16”S 46º05’44”W, 5 m a.s.l., 05.III.2024, fl., L. C. Marinho et al. 2130 ( HUEFS!, HURB!, LAG!, MAR!, RB!) .

Distribution, habitat and phenology. — Calea breviflora was found in two locations, ca. 19 km apart, in Carutapera and Boa Vista do Gurupi municipalities, Maranhão, Brazil ( Fig. 3 ). Plants grow in white sand ecosystems, characterized by oligotrophic sandy soils at elevations of 5 m a.s.l. Specimens were collected with florets and fruits in May and October.

Preliminary conservation status assessment. — Calea breviflora is known from only two subpopulations, ca. 19 km apart from each other, in the northwestern portion of Maranhão, which corresponds to the easternmost portion of the Amazon domain. This region is considered part of the Deforestation Arc, where intense activity of livestock grazing and plantation advances towards the forest and promotes the highest rates of deforestation of the Amazon ( Nepstad et al. 1995). None of these known subpopulations are included in a protected area and, according to the IUCN criteria (2012) B1ab (i, ii, iii, iv) and B2ab (i, ii, iii, iv), the species is assessed as Critically Endangered (CR). Also, the species is known from only two localities with a continued decline of the habitat quality mainly due to cattle grazing and sand extraction.

Etymology. —The epithet “ breviflora ” is the combination of the Latin terms “brevis”, which means short, and “flora”, floret. This epithet was chosen to refer to the unusual short length of the florets in Calea breviflora , which is among the five Calea species with the smallest ray florets, and among the two Calea species with the shortest disc florets.

Suggested vernacular name. — Calea species are commonly called “margarida-amarela”, in Portuguese (yellow daisy, free translation), due to their generally yellow inflorescence and in reference to their common similarity to all daisies. We suggest, for C. breviflora , the vernacular name “margaridinha-da-campina” (little daisy of campina, free translation), in reference to the florets’ size and the white sand ecosystem where it was collected.

Notes. —The Brazilian species that is most similar to Calea breviflora is C. candolleana (Gardner 1848: 414) Baker (1886: 256) , due to the herbaceous habit, phyllaries, and the short pappus scales. These shared morphological characters justify that C. breviflora belongs to C. sect. Candolleanae (sensu Bueno et al. in press). Calea breviflora diverges from C. candolleana by the petiole 0.9–2.45 mm long (vs. 3.6–4.2 mm), leaf blade lanceolate or ovate (vs. elliptic), abaxial leaf surface pilose to hirsute (vs. strigose), involucre cylindrical (vs. campanulate), 4.6–6.95 mm wide (vs. 7.3–10.4 mm wide), ray floret corolla 3.2–4.3 mm long (vs. 6–12.6 mm long), disc floret tube 0.6–1 mm long (vs. 1.4–2 mm long), and pappus scales 1–1.3 mm long (0.2–0.3 mm long).

The Calea divaricata clade is characterized by the herbaceous habit, leaves narrower than 2 cm, no more than seven ray florets per capitula, and pappus scales smaller than cypselae; the new species matches with these characters.

Inserted in this clade, Calea caleoides ( Candolle 1838: 294) Robinson (1975: 428) is most similar to C. breviflora due to its narrow leaf blades (<2 mm wide), involucre <7 mm (long and wide), ray florets and disc florets <5 mm long, and cylindrical cypselae. Another morphological trait shared is the epaleaceous receptacle. Calea caleoides is historically considered an epaleaceous species ( Candolle 1838; Robinson 1975); however, VRB studied in person specimens from the US herbaria and found 1-paleae receptacle, which can be classified as pauperpaleaceous (Bueno et al. 2022), which may indicate that this character needs to be better examined in the genus. Calea breviflora can be distinguished from C. caleoides by its petiole 0.6–0.7 mm long (vs. 1.3–4.2 mm long), second series of phyllaries with apex foliaceous (vs. scarious), 7–14 disc florets per capitulum (vs. 18–20 per capitulum), and cypselae 1.8–3 mm long (vs. 3.25–3.5 mm long).

Calea breviflora is the first Brazilian species of the C. divaricata clade. Its geographic distribution (in northern Brazil) can provide important information to biogeographically explain the relationship between this clade and C. sect. Candolleanae (sensu Bueno et al. in press), which only includes species endemic to Brazil and occurring in the centerwest and north-east (Bueno et al. in press). The first identification key for the C. divaricata clade is provided below.

Figures

FIGURE 1. Calea breviflora sp. nov. A. Flowering branch. B. Leaf abaxial surface. C. Details of the capitulum, without the ray florets. D–I. Involucre sequence of phyllaries. J. Ray floret without pappus scales. K. Disc floret without pappus scales. L. Details of the cypselae and pappus. M. Watercolor of the capitulum. A–L illustrated by Débora Dalzotto and M by Leonardo Nascimento.

FIGURE 2. Calea breviflora sp. nov. A–B. Habit. C. Detail showing the leaf abaxial surface. D–F. Head highlighting phyllaries, ray florets, and disc florets. G. Cypsela and pappus scales details. H. Habit, arrow pointing to the local where the individual was collected. I. M.S. da Silva collecting specimens of C. breviflora. Photos by Lucas C. Marinho.

FIGURE 3. Distribution map of Calea breviflora sp. nov.