Passiflora acreana Mezzonato & Silveira, 2023

Mezzonato-Pires, Ana Carolina, Silveira, Marcos & Oliveira, Mayk Honório De, 2023, Passiflora acreana, a new species of Passiflora subgenus Passiflora (Passifloraceae sensu stricto) from Acre, Brazil, Phytotaxa 579 (1), pp. 39-46 : 40-43

Passiflora acreana Mezzonato & Silveira , sp. nov. ( Figs. 1 and 2 ).

Type:— BRAZIL. Acre: Rio Branco, APA Lago do Amapá. Bacia do rio Acre, margem direita do rio Acre, 10º03’18.0”S, 67º51’30.7”W, 147 m. a.s.l., 25 January 2020, M. Oliveira, M. Silveira, I. Oliveira, C. Gonçalves, L. Guimarães & M. Caniso 105 (holotype CESJ!, isotype UFACPZ!)

Passiflora acreana differs from the similar P. garckei by stipules with awns 2.8–3.1 mm long (vs. absent) and petiolar pedunculate glands with the apex concave (vs. patelliform); from P. gardneri it differs by having ten (vs. five) series of corona filaments 29.4–38.5 (vs. 20–25) mm long; and from P. eichleriana by the corona filaments whitish to basally purple, followed by a white band, which may be absent, and lilac to purple-bluish in the remaining 2/3 (vs. completely white), and arranged in ten (vs. six) series.

Liana with tendrils. Branches 0.7–2.8 mm diam., brown, brown-greenish, cylindrical, striate, pilose. Stipules 9.4–20.4 × 4.6–7.4 mm, awns 2.8–3.1 mm long, foliaceous, reniform. Petiole 15–52.6 × 0.4–1 mm, pilose; glands (3)4–8, 0.6–0.8 × 0.5–0.8 mm, pedunculate, the apex concave, spaced or in pairs, distributed along the petiole. Leaf blade 3-lobed, 2.7–13.9 × 3.7–11.5 cm, united portion 1.3–5 cm long, lateral lobes 1.3–3.6 × 1.4–4.5 cm, ovate, central lobe 1.1–6.1 × 1.1–5 cm, ovate, ovate-lanceolate, apex acute to obtuse, mucronate, base slightly truncate to truncate, abaxial surface pilose, adaxial surface glabrous, except in the midrib, secondary veins and margin; margin entire, with 3–6 circular glands, slightly pedunculate, in the sinus of leaf blade, 0.2–0.4 × 0.3–0.5 mm, and 0–2 glands in the base of leaf blade. Inflorescence 1-flowered. Peduncle 17.6–32.4 mm long. Bracts 3, 11.6–29.9 × 4.4–15.6 mm, verticillate, pilose, oblong, ovate to ovate-lanceolate, margin entire, glandular at the base. Pedicel 0.8–5.1 mm long. Flowers ca. 63.6 mm diam., hypanthium campanulate, glabrous; sepals 24.6–36 × 8.2–8.4 mm, oblong-lanceolate, apex obtuse, carinate-cucullate with awn 3–3.6 mm long, abaxial surface centrally green, white on the lateral and adaxial surface, glabrous, with few trichomes on the midrib abaxially; petals 24.8–35.1 × ca. 8 mm, linear-oblong, apex obtuse, white to lilac, glabrous; corona with 10 filament series, two outer series 29.4–38.5 mm long, filiform, whitish to purple at the base, followed by a white band, which may be absent, and lilac to purple-bluish on the remaining 2/3 of filaments length; other inner series 2.2–5,5 mm long, capitate, rarely bifid, purplish, innermost filaments near the androgynophore purplish, with white to light pink apex; operculum 7.7–11.8 mm long, united portion 2.3–3.1 mm long, membranaceous at the base, free portion 5.4–8.7 mm long, filamentous at the apex, exserted, pinkish; nectar ring present; limen ca. 4 mm long, membranaceous, adnate to androgynophore, apex slightly wavy; androgynophore ca. 17.2 mm long, trochlea absent; stamen filaments 8.7–9.4 × 1–1.4 mm, glabrous; anthers 11–11.2 × 2.4–3.1 mm; ovary 5.8 × 2.6 mm, elliptic, glabrous; style 10.7–14.3 long, 0.5–1 mm diam. Fruit 5.8–8 × 3.7–7 cm, globose, glabrous, immature green immature, mature yellow; seed 4.8–5.5 mm long, 2.9–3 mm larg., 1.1–1.3 mm thick, obovate, reticulate.

Paratypes:— BRAZIL. Acre: Rio Branco , APA Lago do Amapá. Bacia do rio Acre, margem direita do rio Acre, 10º03’18.0”S, 67º51’30.7”W, 147 m. a.s.l., 17 November 2018, M. Oliveira et al. 14 (CESJ, UFACPZ); Rio Branco , APA Lago do Amapá. Bacia do rio Acre, margem direita do rio Acre, 10º03’18.0”S, 67º51’30.7”W, 147 m. a.s.l., 26 April 2019, M. Oliveira et al. 66 (CESJ, UFACPZ); Rio Branco , APA Lago do Amapá. Bacia do rio Acre, Bacia do rio Acre, margem direita do rio Acre, 10°02’35.1”S 67°52’24.1”W, 137 m. a.s.l., 29 January 2022, M. Oliveira et al. 418 (UFACPZ); Rio Branco , APA Lago do Amapá. Bacia do rio Acre, Bacia do rio Acre, margem direita do rio Acre, 10°02’38.0”S 67°52’27.8”W, 135 m. a.s.l., 01 February 2022, M. Oliveira et al. 422 (UFACPZ); Rio Branco , Estrada da Floresta, BR 364, Via Verde, margem esquerda do rio Acre, 10°00’11.9”S 67°50’57.4”W, 171 m. a.s.l., 30 November 2020, M. Oliveira et al. 202 (UFACPZ) .

Distribution and habitat: —The species is not abundant in the area, occuring predominantly on the edges of an alluvial open forest with palm trees and bamboos of the genus Guadua Kunth (1822: 252) in an intermediate alluvial terrace.

Phenology:— Passiflora acreana was collected with flowers in November, January and February, and with fruits in April.

Etymology: —The specific epithet “ acreana ” is a tribute to Acre, the state where this new species was found.

Conservation status: —Thus far, only four populations of P. acreana have been found ( Fig. 2 ). Three populations occur in the Lago do Amapá Environmental Protection Area, Rio Branco, Acre State, and the fourth occurs in the surrounding areas of the conservation unit. The species has an estimated extent of occurrence of 7,585 km 2 and an estimated area of occupancy of 16,000 km 2, being therefore categorized as critically endangered (CR), B1ab (i,ii,iii) + 2ab (i,ii,iii) following the IUCN Red List criteria (IUCN 2022). Although three of its populations are located in the conservation unit, P. acreana generally occurs on the edges of small forest fragments threatened by their close proximity to residential buildings and anthropogenic activities, such as burning and clearing.

Features and affinities:— Passiflora acreana is placed in P. subg. Passiflora , supersect. Stipulata sect. Granadillastrum .

The species can be easily distinguished from morphologically similar species by the presence of pilose indumentum throughout the plant surface, except on the leaves adaxial surface and ovary; foliaceous reniform stipules with awns and (3)4–8 petiolar pedunculate glands, with the apex concave, spaced or in pairs; corona with ten series of filaments, whitish to purple at the base, followed by a white band, which may be absent, and lilac to purple-bluish on the remaining 2/3 of filaments length, innermost filaments (near the androgynophore) purplish with apex whitish to light pink.

Passiflora acreana is similar to P. eichleriana Masters (1872: 568) , P. gardneri Masters (1872: 566) , and P. garckei Masters (1871: 639) (Fig. 4). The main comparative features among these species are described in Table 1 . Only P. garckei occurs exclusively in the Amazon domain ( Bernacci et al. 2020). Passiflora acreana can be differentiated from P. garckei for being pilose (vs. glabrous), with pedunculate glands with the apex concave (vs. sessile, patelliform glands), stipules with (vs. without) awns. Passiflora acreana can be distinguished from P. eichleriana for having stipules with (vs. without) awns and with pedunculate glands with the apex concave (vs. ligulate glands); furthermore, while P. eichleriana flowers are white, P. acreana bears flowers with corona whitish to purple at the base, followed by a white band, which may be absent, and lilac to purple-bluish in the remaining 2/3 of filaments length. Passiflora acreana differs from P. gardneri by its reniform (vs. semi-ovate) stipules, with smaller awns (2.8–3.1 mm vs. ca. 5 mm long), and corona with 10 (vs. 5) series of filaments.

Illustrations and/or photographs of these similar species can be found in Cervi (1997, Fig. 12), Koch et al. (2014, Figs. 1b and 2a ), and Koch et al. (2019, Figs. 1 and 2 ).

With this new species, the state of Acre now harbors 29 species ( Bernacci et al. 2020), two of which ( P. bernaccii and P. kikiana Cervi & Linsingen (2010: 1062)) were described in the last 11 years. Among these species, Passiflora jussieui Feuillet (2010: 611) and P. ovata Joseph Martin ex De Candolle (1828: 322) were recently recorded for the first time in Brazil ( Mezzonato-Pires et al. 2018), whereas P. costata Masters (1872: 573) , previously recorded in other Brazilian states, was for the first cited for Acre in 2017 ( Mezzonato-Pires et al. 2017). These records, added to the description of the new species P. acreana , reveal the importance of expeditions in Acre for enhancing the knowledge of the Brazilian flora, particularly with regard to Passifloraceae taxonomy, and the relevance of conservation units for biodiversity conservation.

Figures

FIGURE 1. Passiflora acreana Mezzonato & Silveira.A. leaf blade. B. pedunculate glands. C. stipules. D. flower.E. longitudinal section of flower. F. inner filaments. G. bracts. H. abaxial surface of sepals. I. fruit. J. longitudinal section of fruit. K. seeds.

FIGURE 2. Distribution of Passiflora acreana Mezzonato & Silveira in the Lago do Amapá Environmental ProtectionArea,Acre, Brazil. Source of image: Google Earth. Map data ©2022 Google. Images courtesy of ©2022 CNES Airbus via Google Earth.