Passiflora dendroidea Kuethe & Cornejo, 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 : 150-152

1. Passiflora dendroidea Kuethe & Cornejo , sp. nov. ( Figure 2 )

Type:— ECUADOR. Pichincha: San Miguel De Los Bancos Canton, San Miguel De Los Bancos Parish, Pueblo Nuevo Campus, Artenschutzstiftung Foundation restoration area Karlsruhe Zoo - Kek Germany Project, water protection area. Cloud forest, 0°00’20.61”S 78°47’0.09”W, 1560 m, 18 April 2024 (fl.), N. Mejía 450 (holotype GUAY! (no barcode): isotype QCA! (no barcode)).

Diagnosis:— Passiflora dendroidea is similar to Passiflora magnoliifolia but differs markedly in the size and habit of mature specimens (20 m and multiple branched vs. 5–7 m and few-branched); size of the flowers (7–8 cm wide vs. 5–6 cm); and shape and texture of the fruit (subglobose to pyriform with glaucous exocarp vs. globose with pubescent exocarp). They further differ in their respective distributions, with P. dendroidea being found in the northwestern Ecuadorean Andes while P. magnoliifolia is from central Cordillera, Colombia.

Description:— Habit a medium-size free-standing tree up to 15 m high and 15–20 cm DBH, well-branched and leafy in upper portion, glabrous throughout, except ovary; occasionally with some very fine pubescence present on the abaxial surface of the youngest leaves. Trunk wooded, stout, with (sub-)vertical shallow grooves, sometimes somewhat flaky, richly lenticellate. Stems stout, woody, deep brown, terete. Stipules subulate, often deciduous, 1.0– 1.5 mm long 1.0 mm diameter at base, dark green to brownish. Petioles stout, 2.5–4.5 cm long, abaxially terete, longitudinally 2-ribbed and channelled adaxially, with one to two (one major and one minor) protruding and adaxially flattened glands on each side of the midrib at base of the leaf blade; glands a dusty olive-green to yellowish or purple colour. Leaves simple, coriaceous to thinly chartaceous, obovate to obovate-elliptic, 15–30 cm long 10–18 cm wide, rounded to shortly acuminate or obscurely emarginate and mucronate at apex, the mucro up to 1 mm (subacute apices were occasionally seen in juvenile plants), broadly obtuse to subtruncate and often somewhat oblique at base, margins slightly thickened, revolute, often with 1 to few glands at base, adaxial surface deep green, abaxial surface very pale green to whitish-green, becoming a fresher green at maturity, glabrous; prominently pinnately veined, lateral veins 9–15, inter-secondaries present, tertiaries reticulate. Peduncles up to 5–7 cm long, sturdy to slightly wooded, subhorizontal to semi-pendent, once dichotomous to trichotomous just below or at the middle (very occasionally twice dichotomous given three flowers per peduncle), articulated at apex; pedicels 1.0– 2.3 cm long, curved giving the flower a upwards orientation. Bracts minute to absent, 0.5 mm if present, dark green to blackish, soon deciduous, absent in all open flowers. Flowers 7–8 cm in diameter when fully open, white with yellow, sweetly scented; hypanthium campanulate, 1.2–1.4 cm deep, 0.8–1.0 wide at base, white with green veins on the outside, yellowish-white on the inside; sepals oblong to ovateoblong, 2.8–3.5 cm long 1.3–1.6 cm wide, rounded at apex, white to whitish-yellow on the abaxial surface, pure white on adaxial surface, ecorniculate; petals subequal to sepals, 2.7–3.6 cm long 1.0– 1.3 cm wide, white on both surfaces, reticulately veined, thinly membranous; corona filaments arranged in 2 well-defined series, yellow to yellow with white; outer series distinctly dolabriform, 16–18 mm long, with the upper portion falcate, about 6–8 mm long terminating in an acute tip, deep yellow becoming gradually whitish in lower third; inner series small, broadly linear, 2–3 mm long, deep yellow with a white to whitish base, slightly inclined; operculum thick filamentose nearly to base, divided into fleshy linear segments, whitish-yellow, strongly inclined towards the base of the androgynophore forming a barrier; androgynophore greenish-white, 18–20 mm long, distinctly thickened in the basal quarter; staminal filaments pale green, 7–10 mm long; pollen deep yellow. Ovary ovoid, whitish to whitish-yellow, densely pubescent with whitish trichomes; styles pale green to greenish-yellow, 5–6 mm long; stigma whitish-green. Fruit a globose to semi-globose capsule, occasionally somewhat pyriform, 3.5–5.0 cm long 3.2–4.5 cm in diameter, tomentulose to glaucous, very pale green with a whitish coating; exocarp hard, brittle; mesocarp white to whitish green, juicy, 3.0–5.0 mm thick. Mature seeds broadly ovoid, foveolate, shallowly pitted, black; germination (from scattered seedlings) epigeal.

Phenology:— Passiflora dendroidea was seen with flowers, buds and ripened fruit during August, February and April, which implies a prolonged, but sporadic flowering pattern as no flowers were seen in December or May. In its native region, these months correspond mostly with the rainy season. The tree exhibits a deciduous behaviour between January and February.

Etymology:—The term “ dendroidea ” is derived from the Greek words “dendro-” meaning “tree” and “-oid” meaning “like” or “resembling”. This was chosen in reference to its tall, tree-like habit.

Distribution:— Passiflora dendroidea is found along the western fringes of the central to northwestern Ecuadorean Andes, with populations sighted in the provinces of Pichincha and Imbabura. Notable populations were observed within the El Cedros reserve, Mindo, Intillacta and Guaycuyacu, which are lower cloud forest reserves in the western foothills of the Andean Cordillera. The populations are seen at elevations between 1500 and 2100 m, where the west-facing Andes is characterized by dense stratified, montane wet cloud forest. The trees are seen, though substantial in size, as a mid-canopy inhabitant of the biome, with partial sunlight reaching the tree crown.

Conservation status:—Using the three main populations recorded gives an Extent of Occurrence (EOO) of 295–300 km 2, with an Area of Occupancy (AOO) of 32 km 2. The species appeared to be common within each of its study areas, where both fruit and seedlings have been seen at all three populations, and it may be that exploratory collections in future will reveal new points of its occurrence. Based on the current findings, a conservation assessment of VU (Vulnerable) is proposed here based on ( IUCN 2022) criteria B2ci,ii,v, C2b and D2.

Notes:— Passiflora dendroidea belongs to P. subg. Astrophea where it straddles a close affinity with the similarly arboreal species Passiflora magnoliifolia Dietr. (1819: 617) (hereto P. arborea Spreng. (1826: 42)) and P. emarginata Bonpl. (1806: 23) . Both P. magnoliifolia and P. emarginata are endemic to Colombia, where they can be found in the volcanic Central Cordillera within the departments of Tolima, Quindio, Valle de Cauca, Caldas, Cauca, Antioquia and Risaralda. P. magnoliifolia , or P. arborea , has been a complicated taxonomic entity due to the many erroneous allocations of the name, assigning many subtly different arboreal species the taxon despite there being no ecological, or even morphological overlap. The same was done with the populations from Ecuador, here assigned as P. dendroidea but noted as “ Passiflora arborea ” in previous surveys such as Holm-Nielsen et al. (1988), Jorgensen & MacDougal (1997), Hilgenhof (2013, 2017) and Mezzonato-Pires et al. (2017). Tigrero & Norrbom (2020) also located P. dendroidea , but mistakenly identified it for P. putumayensis .

Passiflora dendroidea is one of only 16 truly arboreal species meaning that it does not produce any tendrils at any stage of its lifespan. Narrowing it down further to just one of six, it belongs to a small group of species with the potential of growing into tall (> 10 m), multibranched trees, of which the canopy reaches the top or midlevel of forest canopy stratification. This is substantially different from other true Astropheas such as P. macrophylla , P. grandis Killip (1938: 531) or P. putumayensis , which are reduced to [small] understory arched treelets that generally do not reach heights of two meters or more and are mostly single stemmed with no- or limited branching except when stems are broken off. P. magnoliifolia , which is an intermediate herein with heights of up to 5–7 m and moderate branching remains solely within the understory of its respective environment which, as per the type species, is within the volcanic to subvolcanic central cordillera of central Colombia. P. emarginata , which is the taller species with a height potential of 10–15 m making it much more akin to P. dendroidea in size and habit, is restricted mostly to the valleys and east-facing Andes of the Cordillera Occidental in central-south Colombia (departments of Cauca and Valle de Cauca). P. dendroidea differs from both above mentioned species in its distribution being restricted to the [non- to subvolcanic] west-facing Andes and western Andean foothills, where it grows in low-level cloud forest around the equatorial latitudes.

In general morphology, the species from this alliance are all very closely related, to the point that identification can be difficult if no habitat or distributional information is provided. Passiflora dendroidea is most distinctive by its tomentulose to glaucous, weakly pyriform to subglobular and whitish fruit; whereas in both P. magnoliifolia and P. emarginata the fruit are distinctly pubescent to tomentose, ribbed, globose in shape, and remain green to green with a brownish tinge. The leaves of P. dendroidea show a whitish lustre underneath, which can only be seen subtly in some younger plants of P. magnoliifolia but is generally absent in P. emarginata ; and are rounded to slightly emarginate at apex only seen in P. emarginata but not in P. magnoliifolia . The flower of the new species is relatively large, with a diameter of 7–8 cm while in the other species the flowers are generally 5–7 cm at most. In addition, the Ecuadorean distribution of P. dendroidea makes it allopatric in relation to the species mentioned above.

Figures

FIGURE 2. A Lankester Composite Dissection Plate (LCDP) of Passiflora dendroidea sp.nov. Compiled with photographs taken by Francisco Tobar, J.R. Kuethe and Nicanor Mejía-Pazos.