Acritopappus jacobaeus Bautista, Rodr.Oubiña & S.Ortiz, 2017

Bautista, Hortensia P., Rodríguez-Oubiña, Juan & Ortiz, Santiago, 2017, Two new species of the Brazilian endemic genus Acritopappus (Compositae, Eupatorieae) from Chapada Diamantina, Bahia State, Phytotaxa 311 (1), pp. 22-28 : 23

publication ID	https://doi.org/ 10.11646/phytotaxa.311.1.2
persistent identifier	https://treatment.plazi.org/id/03BA8790-A653-FF8F-FF75-0D92FD52F8D5
treatment provided by	Felipe
scientific name	Acritopappus jacobaeus Bautista, Rodr.Oubiña & S.Ortiz
status	sp. nov.

Treatment

Acritopappus jacobaeus Bautista, Rodr.Oubiña & S.Ortiz View in CoL , sp. nov. ( Fig. 1 View FIGURE 1 )

Acritopappus jacobaeus is rather similar to A. micropappus but mainly differs by its petiolate, papyraceous, and smaller leaves (6–8 × 2–3 cm) with acute apex, and sessile, grouped capitula with a much lesser number of florets (5–6) and receptacular paleae (2–3). By contrast the latter has sessile, coriaceous, and larger leaves (6–10 × 3–4.5 cm) with rounded apex, and pedicellate, often isolate capitula with more numerous florets (18–20) and receptacular paleas (11–13).

Type:— BRAZIL. Bahia State: Municipality of Morro do Chapéu, near the road BA–426 between Morro do Chapeu and Utinga, 4, 1 km after the crossroad with BA–052 to Utinga, swamp soils in open arboreal cerrado, quartzitic sand with an upper turf level, 1050 m, 11°35’S, 41°09’W, 4 October 1997, H. P. Bautista 2381 (holotypus HRB!, isotypus SANT!).

Shrub up to 1.70 m high, scarcely branched. Branches erect-patent, often opposite, subcylindrical, striate, with eglandular, pluricellular, uniseriate, and glandular hairs; internodes 1.5–3 cm long. Leaves entire, opposite, erect-patent, petiolate; petioles 1.5–5 mm, striate, not conspicuously enlarged at base nor fused to petiole of opposite leaf; lamina 6–8 × 2–3 cm, elliptic, flat, deep green at the field, papyraceous, non-viscid; margins often revolute, serrate at the 2/3 distal part, entire at the proximal third part, apex and base acute; adaxial face glabrous, venation pinnatereticulate, slightly prominent; abaxial face with eglandular, pluricellular, uniseriate hairs, scattered throughout nerves, venation prominent. Inflorescence corymbiform, with capitula grouped, peduncles striate, opposite, principal peduncle 6–8 cm long, secondary peduncles 1–3.5 cm long, sparsely bracteate, bracteae 1–3 mm long, narrowly lanceolate, acute, with ciliate margin, capitula grouped, sessile, rarely in very short pedicels. Capitula homogamous with 5–6 florets; involucres 5.6–6.1 × 1.8–2.2 mm, cylindric, with ± 7 phyllaries in 2–3 series; phyllaries 2.3–5.5 × 6– 1.2 mm, elliptic, green, with scariose margins, apically ciliate, apex acute to subobtuse, base irregular, eximbricate; receptacle flat, paleaceous, paleae 2–3, 3.2–4 × 0.2–0.3 mm, flat, elliptic, margins scarious, ciliate, apex and base acute. Florets hermaphrodite; corolla tubular, 3.5–3.6 × 0.6–0.7 mm, with sparse, stipitate glandular trichomes, lilac; corolla tube 2.8–2.9 × 0.4–0.5 mm; lobes 0.6–0.7 mm long, patent to ascending, apex acute, with short papillae located internally in upper part; anthers 1.5–1.6 mm long, apical appendage 0.5 × 0.4 mm, ovate, somewhat longer than wide, with acute, sometimes irregular, apex, anther base slightly acute, collar cylindric, slightly wider at the apex; style ± 5.7 mm long, glabrous; style branches ± 3.5 mm long. Cypsela 2.6–2.8(–3) × 0.6–0.8 mm, black, prismatic, base often asymmetric, glabrous, 5-ribbed, distances between ribs unequal; carpopodium lateral (asymmetrical); pappus 0.4–0.5 mm long, coroniform.

Etymology: —The specific epithet honors Santiago de Compostela, Capital of Galicia, NW of the Iberian Peninsula, since these collections were identified as a new species during the Jacobean year 1999.

Phenology: —The material indicates that this species is in flower and fruit in August and September but it might have flowers and fruits all year long, like other species of Acritopappus (i.e. A. confertus ).

Geographical distribution and ecology: — Acritopappus jacobaeus is only known from the Municipality of Morro do Chapéu, NE Chapada Diamantina in the Bahia state of Brazil. The new species grows on swampy grounds where green patches of plants are interspersed within a mostly arid cerrado vegetation.

Additional specimen examined: — BRAZIL. Bahia State: Municipality of Morro do Chapeu, 6 km from Morro do Chapéu city on the road BA–426 to Utinga, swamp grounds in cerrado vegetation, sandstone and hidromorphic podzol soils, 900 m, 11º35’30”S, 41º09’49”W, 24 August 1998, H.P. Bautista & J. Rodríguez-Oubiña 2508 (HRB!, SANT!).

Discussion: —The species most morphologically similar to A. jacobaeus seems to be A. micropappus ( Baker 1876: 198) King & Robinson (1977: 100) , which is quite frequent in NE of Chapada Diamantina and in Serra de Jacobina. Acritopappus prunifolius King & Robinson (1980a: 144) , a species rather common in central and southern areas of Chapada Diamantina, also presents some morphological similarities with A. jacobaeus . Main differences between these three taxa are shown in Table 1.