Passiflora panguiensis Kuethe, 2025

Kuethe, J. R., Cornejo, Xavier, Garzón-Suárez, Henry X., Jiménez, Marco M., Wettges, Martin, Magdalena, Carlos, Mejía-Pazos, Nicanor, Flores, Juan Carlos Espín & Decoux, Jose, 2025, Passionflower trees of Ecuador: revising the presence of Passiflora subg. Astrophea (Passifloraceae) and including resolution to the P. putumayensis and P. macrophylla taxonomic complexes, Phytotaxa 697 (2), pp. 147-165 : 157-159

5. Passiflora panguiensis Kuethe sp. nov. ( Figure 5 )

Type:— ECUADOR. Zamora-Chinchipe: Yantzaza canton, Cordillera del Condór region, between Yantzaza and Los Encuentros, within the Río Machinaza watershed , 03 o 45’48”S 78 o 31’42”W, 1370 m, 25 June 2009 (fl.), D. Neill & C. Kajekai 16958 (holotype: MO 7023016 !; isotypes: QCNE! (no barcode), MO 7023017 !) .

Diagnosis:— Passiflora panguiensis is similar to Passiflora putumayensis but differs in the length and bifurcation of the peduncles (> 8 cm, once dichotomous vs. <8 cm trice dichotomous), number of flowers per peduncle (2–3 vs. 4–9); and the structure and size of the outer corona (dolabriform, <15 mm vs. erect, wavy,> 15 mm); as well as the length of the inner corona (yellowish white, 1–2 mm vs. stark yellow, 3–4 mm). They further differ in the shape (ovate to ovate-elliptic vs. lanceolate to narrow ovate) of the leaf.

Description:— Habit a small-size, weak to partially free-standing treelet up to 100–175 cm high and 3–5 cm DBH, sparingly branched, glabrous throughout, except ovary. Trunk weakly wooded, stout, somewhat lenticellate. Younger stem stout, olive green, terete. Stipules subulate, very soon deciduous, ~1.0 mm long, brownish. Petioles slender, 1.4–3 cm long, mostly terete, caniculate adaxially, with one to two (one major and one minor) flattened gland(s) on each side of the midrib at base of the leaf blade; glands a dusty olive-green. Leaves simple, membranous to subcoriaceous, ovate to ovate-elliptic, 15–35 cm long 5–13.5 cm wide, acuminate at apex, narrowly rounded to cuneate at base, margins entire, adaxial surface deep green, abaxial surface a paler green, glabrous; pinnately veined, lateral veins 6–8 cm, inter-secondaries present. Peduncles up to (5–) 8–12 cm long, slender, subhorizontal to semi-pendent, curving upwards at point of bifurcation, once dichotomous above the middle, occasionally one of the bifurcated peduncles bifurcated to present a third flower, carrying 2(–3) flowers per peduncle, articulated just below apex; pedicels 1.0– 1.5 cm long, curved giving the flower an upwards orientation. Bracts minute, 1.2–1.5 mm if present, brownish, persistent. Flowers 5.2–6.1 cm in diameter during anthesis, petals and sepals reflexed during the anthesis, white with yellow, sweetly scented; hypanthium campanulate, 5–8 mm deep, 5–6 mm wide at base, white to whitish green on the outside, whitish-yellow on the inside; sepals linear-oblong to linear-ovate, 2.4–2.8 cm long, 1.1–1.3 cm wide, rounded at apex, snowy white on both surfaces, fleshy, ecorniculate; petals subequal to sepals, 2.5–2.8 cm long 1.1–1.2 cm wide, white on both surfaces, very membranous; corona filaments arranged in two series, bright yellow with white; outer series dolabriform, 13.5–14.5 mm long, whitish-yellow in the basal half, gradually becoming yellow in the upper portion up to the point dolabriform orientation, the upper portion falcate, about 5.2–5.6 mm long, slightly thickened in lateral section, bright yellow; inner series minute, broadly linear, 1–2 mm long, pale yellow, gradually becoming greenish-yellow towards the base, radiate; operculum a thin membrane at the base of the androgynophore, 2–3 mm long, white to whitish yellow; androgynophore green to greenish-white, 15–16 mm tall; staminal filaments pale green, 4–5 mm long; anthers 5–6 mm, white to whitish-yellow. Ovary ovoid, whitish to whitish-green, pubescent with whitish trichomes; styles 5–6 mm long, light green; stigma 3.3–3.4 mm, whitish-green. Fruit slightly pyriform to ovoid, circular in lateral cross-section, 4.5–6 cm long, about 3–3.5 cm wide at its widest point, green to yellowish-green nearing maturity, pubescent with whitish trichomes. Mature seeds not seen.

Phenology:— Passiflora panguiensis was seen with flowers during December, May and June, implying a prolonged, but sporadic flowering pattern. Near fully ripe fruit (no flower) was observed in September.

Etymology:—This species is named after the El Pangui municipality, in the southern Cordillera del Condór region. This location appears to be a central point for its distribution.

Distribution:— Passiflora panguiensis is found along the south-western range of the Cordillera del Condór, with populations sighted restricted to the province of Zamora-Chinchipe. Notable populations were observed nearby the towns of El Pangui, Yantzaza and Los Encuentros, as well as the headwaters of the Río Nangartiza and Río Machinaza. The populations are seen at relatively moderate elevations between 1100 and 1400 m, where it grows as a weak arborescent shrub in the understory of dense, stratified rainforest. Populations were seen growing exclusively in sandstone terranes, where it often trails down mud slopes along the sides of forest trails.

Conservation status:—Using the four main populations recorded gives an Extent of Occurrence (EOO) of 100– 115 km 2, with an Area of Occupancy (AOO) of 20 km 2. Fruit has been seen, although no seedlings were observed. Habitat disturbance because of mining and the clearing for grazing throughout the region causes instability and decline of suitable forest habitats. Based on our observations, a conservation assessment of EN (Endangered) is proposed here in line with the IUCN (2024) criteria B1, B2ab, C1, C2ai and D.

Notes:— Passiflora panguiensis , is one of two species here segregated from the P. putumayensis complex. It was first sighted by David Neill ( Neill 13012) during botanical surveys around a mining area in El Pangui in December 2000, and later near Los Encuentros, Yantzaza cantón ( Neill & Kajekai 16958) in 2009. Both these locations are much further south opposed to the reach of distribution where P. putumayensis can normally be found, which is restricted to the northern provinces of Ecuador and foremostly within Sucumbios. Ongoing surveys found additional plants further up the Río Nangartiza and Río Machinaza catchments in 2020 and 2022, photographs of which allowing the specimens to be firmly segregated from P. putumayensis or other arboreal members of P. subg. Astrophea .

Passiflora panguiensis can be distinguished from P. putumayensis by a combination of vegetative traits including the generally weakly frutescent habit that is often seen trailing overground (vs. freestanding); the smaller leaves in flowering specimens (vs.> 20 cm), and the long, once bifurcate peduncles with 2–3 flowers (vs. trichotomous carrying up to 9 flowers). The flowers are different by their relatively short outer corona (<15 mm); small (<2 mm) and white throughout inner series and finely membranous, white opercular structure present at the base of the androgynophore (vs. thick filamentose to denticulate). In contrast, the flowers of P. putumayensis are distinct by the longer (> 2 cm) and subtly wavy corona, the distinct (> 4 mm) and yellow-tipped inner corona, and the fleshy or thick filamentose operculum that is distinctly yellow in the apical half. Furthermore, there is a distinct difference in their respective habitats, with P. panguiensis being found in the cupper-rich sandstone of the premontane hills of the southern Cordillera del Condór, whereas P. putumayensis is found in volcanic regions at the foothills of Volcán Sumaco, Volcán Reventador and Volcán Cayambe, and the Orito Ingi-Ande in Colombia.

Figures

FIGURE 5. A Lankester Composite Dissection Plate (LCDP) of Passiflora panguinsis sp.nov. Compiled with photographs taken by J.R. Kuethe and Nicanor Mejía-Pazos.