Passiflora rimarachiniorum Esquerre & Kuethe, 2025

Esquerre-Ibañez, Boris & Kuethe, J. R., 2025, A new species of Passiflora subgenus Astrophea (Passifloraceae) from Northern Peru, Phytotaxa 700 (1), pp. 98-106 : 99-104

Passiflora rimarachiniorum Esquerre & Kuethe , sp. nov. ( Fig. 1 , 2A–2D )

Type:— PERU. Cajamarca: San Ignacio Province. San José de Lourdes District, Cerro Parcos , coffee plantation near Villa Rica town , 1800 m (fl., fr.), 2 October 2020, B. Esquerre 227 (holotype, HUT-65462!; isotypes, CPUN!, HUT-65463!, PRG!) .

Diagnosis:— Passiflora rimarachiniorum is morphologically similar to P. putumayensis , from which it differs by flowers with pubescence near the base of the androgynophore and the base of the styles (vs. glabrous), inner corona filaments (pali) that are linear, 1–2 mm long, and pale yellow at apex (vs. narrowly linear, up to ca. 4 mm long, and deep yellow in the upper ½), and the opercular tip that is white (vs. opercular tip being yellow).

Tree without tendrils, 1–13 m tall, perennial, glabrous throughout except for the ovary, styles, androgynophore and stipules. Stem terete to subterete, becoming woody at maturity, diameter at breast height ca. 18.2 cm, green when young, sometimes with lenticels. Stipules 2, triangular, 2–3 × 1–2 mm, yellowish to brown, puberulous, soon caducous, absent on older branches. Petiole grooved, 3–7 cm long, apically glandular near or on the junction with the lamina, with two yellowish, scar-like glands, glands elliptical to fusiform, 3–4 mm long. Lamina (10–)28–35 × (4–) 9–14 cm, green with lighter abaxial surface, elliptical to obovate or oblong to lanceolate, base acute to rounded, apex variable, acute to rounded, often substantially emarginate in adult plants. Inflorescence successively bifurcated up to three(- four) levels of branching: first order peduncle 0.5–3.5(–4.5) cm long, second order peduncle 0.5–1.5 cm long, third (and fourth, if present) order peduncle 0.5–1 cm long, carrying up to 6–8 flowers per inflorescence. Pedicel 1–1.5 cm long. Bracts and bracteoles linear to lanceolate, green, (1–)2–4 × 0.5–1 mm. Flower bud elongated and rounded at the apex, with a narrowing at the base, greenish with whitish hues. Flower (3–) 4–5 cm in diameter, facing upright, marcescent. Hypanthium campanulate to narrowly campanulate, 1–1.3 × 0.6–0.7 cm. Sepals linear-oblong, obtuse at apex, green or whitish-green abaxially, white sometimes with green spots adaxially, 2–2.5 × ca. 0.5 cm. Petals oblong, obtuse at apex, white, 2–2.5 × 0.3–0.5 cm. Corona biseriate, yellow becoming slightly white at base, outer series (radii) (0.8–)1–1.5 × ca. 0.1 cm, comprised of 29–33 filaments, linear to wavy in the lower half, dilated and falcate in the upper third, compressed laterally, white at base turning yellowish towards the middle and totally yellow to orange towards the apex; inner series (pali) 0.1–0.2 cm long, linear, slightly dilated at the base, whitish becoming pale yellow or greenish at apex. Operculum 0.3–0.5 cm high, basally entire and slightly segmented, margin lacerated and recurved towards the androgynophore, white, inserted 2–3 mm above the base of the hypanthium. Nectar chamber whitish to yellowish. Limen absent. Trochlea absent. Androgynophore 14–16 mm long, whitish to greenish with the base slightly widened and shortly pubescent at the level of operculum. Stamens 5, filaments 4–5 × 1 mm, white to greenish, anthers 5–5.5 × 2–2.5 mm, cream to pale yellow. Ovary narrowly oblong, tomentose, white to yellowish, 5–6 × 2–2.5 mm, pubescent. Styles 3, 4.5–5 mm long, greenish, pubescent near the base, stigmas 1–1.5 mm, greenish to creamy yellow. Fruit ovoid to ellipsoid, 5–5.5 × 2–3 cm, green when immature, yellowish when ripe, endocarp whitish, arils whitish to greenish in color. Seeds 4.8–5 × 3.5–4 mm, brown to blackish, ovate, with apical horn to one side, crested along margin, reticulate-foveate surface.

Additional specimens examined:— Passiflora rimarachiniorum . PERU. Cajamarca: San Ignacio Province, San José de Lourdes District, Cerro Parcos , 05°04’06”S, 78°53’13”W, 1780 m, 20 December 2016, [fl], Esquerre 158 (HUT) ; Cerro Parcos , 05°04’14”S, 78°53’13”W, 1810 m, 2 October 2020, [fl], Esquerre 226 (CPUN) ; Cerro Parcos , 05°04’12”S, 78°53’14”W, 1800 m, 2 October 2020, [fl], Esquerre 228 (CPUN) .

Additional specimens examined of related species examined:— Passiflora putumayensis . COLOMBIA. Putumayo: La Tortuga, May 1935, [fl], H. García Barriga 4630 (US!) ; ECUADOR. Morona-Santiago: NW range of Cordillera del Cóndor, 1850 m, 7 January 1972, [fl], B. MacBryde 1000 ( MO!). Passiflora aff. putumayensis . Sucumbíos: Cofan community of Alto Bermejo , 00°19’17.7’’N, 77°25’10’’W, 1700-1920 m, 2 August 2001, [fl], R. Aguinda et al. 1518 (F!) ; PERU. Pasco: Oxapampa, old road Oxapampa-Cerro de Pasco, 10°35’S, 75°06’W, 900 m, 15 July 2003, [fl], H. van der Werff et al. 18484 ( MO!) ; Oxapampa, Parque Nacional Yanachaga-Chemillén , 10°17’53’’S, 75°30’54’’W, 1923 m, 11 February 2009, [fl], R. Vásquez et al. 35195 ( MO!) .

Ecology and distribution:— Passiflora rimarachiniorum is known only from the semi-dry montane forests of northern-central Peru, where it was found in the forested slopes of the mountains in the Cajamarca department. The main population of this species can be found in the mountains of the San José de Lourdes District in the San Ignacio Province, where about 10 individual plants have been observed. Most of these trees were seen while being in juvenile stages, sometimes featuring early flowering phases. Only a single mature, wooded and large arborescent individual was found in 2020.

Passiflora rimarachiniorum grows as a tall, freestanding shrub in open vegetation at elevations between 1700 to 1900 m.a.s.l. It was additionally observed that the trunk of the mature individual was densely covered with mosses and lichens, providing a phorophytic habitat within its native biome. The flowers of the new species were seen visited by native bees (Meliponini spp.) (Edwal Rimarachín, pers. corr. 2020), while species of fruit fly (possibly Anastrepha spp. ) show to be actively damaging the flowers ( Vanderplank et al. 2017, Tigrero & Norrbom 2020).

Phenology: — Passiflora rimarachiniorum was observed with flowers from September to December, which corresponds with the beginning of the wet season.

Etymology: —We dedicate this new species to the brothers Edwal and Reys Rimarachín Mena, who kindly accommodated us at their home near Villa Rica and acted as our guides whilst carrying out our botanical studies that led to the discovery of this new species.

Preliminary conservation status: —Since excursions to the area in Cerro Parcos started in 2015, about 10 individual plants have been observed in situ. In the year 2020, a single large and fully mature individual was found measuring 13 m in height ( Fig. 2A ). At present, Passiflora rimarachiniorum is known only from 11 individuals growing in or near coffee farms and rural roadsides, along cloud forest in Cerro Parcos and in the vicinities of Villa Rica town in San Jose de Lourdes District (San Ignacio Province, Cajamarca Department). It should be considered Critically Endangered (CR) based on assessment criteria B1, B2biii, C2i,b and D ( IUCN 2022). This assessment is further supported by having a AOO (Area of Occupancy) of 4 km 2, with an EOO (Extent of Occurrence) of 0.079 km 2. The observed habitats are significantly disturbed by farming and deforestation, reducing the quality of the forest and potentially the ability for the species to sustain itself in future.

Discussion: —According to the current infrageneric classification of Passiflora , the subgenus Astrophea is systematically divided into two supersections: P. supersect. Astrophea ( De Candolle 1822: 435) MacDougal & Feuillet (2003 [2004]: 35) and P. supersect. Pseudoastrophea ( Harms 1925: 498) Feuillet & MacDougal (2003 [2004]: 35), with approximately 27 and 30 species, respectively. Passiflora rimarachiniorum should be included in supersection Astrophea for its arborescent, woody habit without tendrils ( Fig. 2A ), and the white to greenish-white flowers with a bright yellow corona ( Fig. 2D, 2E ). Within this supersection, we consider Passiflora putumayensis Killip (1938: 532) as the closest species to P. rimarachiniorum and the morphological similarities and differences are detailed below.

Vegetatively, the species of P. supersection Astrophea are extremely similar, meaning that the best proxies for identification between species lie in the inflorescence and floral morphology. Passiflora putumayensis is usually seen carrying two flowers per peduncle (once bifurcate), though in rare occasions it was observed having 4–9 flowers per inflorescence ( Ulmer & MacDougal 2004) ( Fig 3A ). In contrast, the inflorescences of P. rimarachiniorum always bears 6–8 flowers ( Fig. 3D ), borne through three (or four) orders of bifurcation. The pali (internal corona) of P. putumayensis is deep to dark yellow in the upper ½ of the filament, with the filaments being narrowly linear and up to 3–4 mm long ( Fig. 3G–I ); whereas in P. rimarachiniorum the pali is white or white with pale yellow to greenish at apex, and the filaments are thicker and up to 2 mm long ( Fig. 1E–F , 3K–M ). Regarding the indumentum, both species present pubescent ovaries, but while P. rimarachiniorum presents an additional tomentose indumentum at the base of the styles ( Fig. 1G ) and the basal area of the androgynophore ( Fig. 1J , 3L ), in P. putumayensis these portions of the flower are glabrous. Though subtle, there are also consistent differences in androgynophore structure between these species. The androgynophore is green with a slight widening at the level of the throat in P. rimarachiniorum ( Fig. 3L ), whereas the androgynophore is white to whitish-green and straight throughout in P. putumayensis ( Fig. 3H ). The opercular margin in P. rimarachiniorum is white ( Fig. 1I , 3L ), while in P. putumayensis the margin is deep yellow ( Fig. 3H ). Lastly, the fruits of P. rimarachiniorum are ovate to ellipsoid and up to 5.5 cm long ( Fig. 1K , 2G , 3N ), while they are ellipsoid and up to 3 cm long in P. putumayensis ( Fig. 3J ).

The new species also shows morphological similarities with the Colombian Passiflora magnoliifolia F. Dietr. (1819: 617) , formerly Passiflora arborea Spreng. (1826: 42) , and their diagnostic morphological differences are outlined in Table 1.

Finally, Passiflora frutescens , native to Huánuco Department and endemic to Andean central Peru, is the only other Peruvian species of P. supersect. Astrophea . It is known only from the type specimen and has not been collected for over 240 years. This species was described as having flowers that are “densely red-spotted” with a funnel-shaped hypanthium, bifurcate peduncle, a corona (presumably the radii) bearing “knoblike projections” at the point of greatest width. The vegetative organs were described to retain a fine puberulous vestiture ( Killip 1938). All these traits readily contrast with P. rimarachiniorum , which has white flowers with a campanulate hypanthium, inflorescence successively bifurcated, radii without projections and glabrous vegetative organs.

Figures

FIGURE 1. Passiflora rimarachiniorum Esquerre & Kuethe:A) Habit; B) Stipules; C) Petiole glands; D) Flower; E) Flower cut; F) Radii and pali; G) Gynoecium; H) Stamen; I) Operculum; J) Floral cup; K) Fruit; L) Seed. LCDP designed by B. Esquerre-Ibañez composed of photographs taken in situ.

FIGURE 2. Passiflora rimarachiniorum Esquerre & Kuethe: Type specimenA) Habit; B-C) Leaves; D) Inflorescence with buds.Another specimen E) Buds and flower; F) Leaves; G) Fruits (Photos: A–G by B. Esquerre-Ibañez).

FIGURE3.Passifloraputumayensis:A)Inflorescence;B–C)Openflowers;G)Flowerlongitudinalcut;H)Androgynophoreandoperculum; I) Pali; J) Fruit. Passiflora rimarachiniorum: D) Inflorescence; E–F) Open flowers; K) Flower longitudinal cut; L) Androgynophore and operculum; M) Pali; N) Fruit (Photos:A–C, G–J by Ronald Boender, D–F, K–N by B. Esquerre-Ibañez).