Passiflora asprantha Kuethe, 2025

Kuethe, J. R., 2025, Re-evaluating the identity of Passiflora hastifolia (Passifloraceae), resulting into a new species of Passiflora ser. Menispermifoliae (Passifloraceae) from North- Central Peru, Phytotaxa 683 (3), pp. 281-288 : 283-287

Passiflora asprantha Kuethe sp.nov. ( figures 1 & 3a,c,e )

TYPE:— PERU. San Martín. Juanjui-Tarapoto road, 20–30 km NE of Juanjui, roadside second growth, 07°15’S, 076°55’W, 400 m, 5 February 1984, A.H. Gentry & D.N. Smith 44969 (holotype: MO!; isotype: MO!) .

Diagnosis:— Passiflora asprantha is different from P. hastifolia and P. menispermifolia by virtue of its white flowers (vs. pink-purple) and the distinct shape of the leaves in which the lateral lobes are consistently offset by 90 o or near (vs. lobation being offset in acute angles of 50 o or less). It is additionally different by the semi-circular stipules (vs. reniform) of which the upper surface is glabrous (vs. pubescent).

Description:— Plant pubescent to sparsely hirsute throughout, 5–6 m long. Stem terete, pubescent to sparingly hirsute. Stipules semi-circular, 0.8–1.0 cm long, 0.3–0.5 cm wide, very short aristate extending into a 1–2 mm long mucro, margins entire, often somewhat recurved, upper surface glabrous, lower surface pubescent. Petioles 2–4 cm long, pubescent, bearing 2 to 3 pairs of opposite, stipitate glands about 1 mm long, upper glands sometimes single (not in a pair), giving the petiole 5 glands in total. Leaves 7–11 cm wide to 7–14 cm long, 3-lobed in an extremely hastate shape with lateral lobes 90 o or near offset from the median, lateral lobes ovoid to oval, with rounded apices, median lobe ovate or ovoid, extending up to 4–6 cm from lobation, lateral lobes about 2–3.5 cm long from base, lobation only in lower quarter the length of the blade, median apex narrow rounded to sub-obtuse to slightly acute, truncate at base and slightly peltate by 1–2 mm, margins entire, glabrescent to pubescent above, densely pubescent to sparingly hirsute below. Peduncles 4–6 cm long, borne singly, pubescent. Bracts borne about 3–5 mm below the base of the flower, somewhat scattered, linear-lanceolate, 3–4 mm long, 1–2 cm wide, somewhat serrate, hirsute to ciliate, often soon deciduous. Flowers white, 5.5–6.5 cm across, sweetly scented with small like Gardenia or Jasmine, with petals and sepals strongly reflexed during anthesis. Hypanthium cup shaped, 8–10 mm in diameter, 2–3 mm in depth, pale green outside and white-yellow on the inside. Sepals linear-oblong, 26–28 mm long, 8–10 mm wide, white to whitish green adaxially green abaxially, obtuse, ecorniculate or with a very obscure, 1 mm, awn present just below the apex, glabrous. Petals subequal to sepals, linear-oblong, 28–32 mm long, 8–9 mm wide, white to whitish green on both sides, thinly membranous. Corona filiform, in 4 series, white throughout, the outer series with filaments 22–26 mm long, radiate, white throughout or with a very feint yellow-beige tinge in the upper third; the second series semi-erect, filiform, 3–4 mm long and inclined outwardly, white throughout, the third and fourth series gradually longer, both ligulate, white throughout; Operculum membranous at base becoming filamentous above, strongly inclined around the androgynophore, the filaments 4–5 mm long, white to whitish green. Limen membranous, 2–3 mm high, closely surrounding the base of the gynophore, green to greenish white.Androgynophore 8–10 mm long, pale green throughout, not speckled. Ovary ovoid, glabrous to somewhat glaucous. Fruits ellipsoid to long-ovoid, 4.2–5.6 cm long, 2.2–3.5 cm wide around midsection, pruinose, greenish yellow to lime-yellow when mature. Seeds ovate, faveolate, 6.5–8 mm long, 3–4 mm wide, dark brown.

Phenology:— Passiflora asprantha was seen with flowers and fruit between July and August, which in its native habitat corresponds with the dry season. The effective pollinator has not been observed, though the structure of the flower and the strong sweet scent it emits suggests pollination by bees.

Etymology:— The specific epithet is derived from the Greek “áspro” meaning “white” and “ánthos” meaning “flower”. This is a reference to the colour of the flower, which is unusual for the members of this taxonomic series.

Distribution:— Passiflora asprantha is restricted to the transitional mountains of the San Martín department of northern Peru. It is commonly seen along the road between Tarapoto and Juanjuí, where it grows at elevations between 350 and 800 m a.s.l. along the edges of dense rainforests and clearings in primary or secondary forests such as roads or riverbanks. It is often seen trailing over small bushes and shrub in the understory of the forest, perceived as a relatively poor climbing vine.

Conservation status:— Using the populations recorded gives an Extent of Occurrence (EOO) of around 2,000 km 2, with an Area of Occupancy (AOO) of about 40 km 2, scaling it as EN (Endangered) in accordance with planimetric criteria. However, it is possible that the full extent of the distribution for Passiflora asprantha is slightly wider, extending into neighbouring reserves and cloud-forested regions. Fruits and seedlings have been seen within these populations, confirming the presence of an effective pollinator. Habitat disturbance and clearing for grazing is seen throughout the region, causing instability and decline of suitable forest habitats. The contemporary conservation assessment of EN is proposed here in line with the IUCN (2024) criteria B1, B2ab, C1, C2ai and D.

Additional specimens examined:— PERU. San Martín. Trail to television antenna, Cerro de la Escalera. Km. 17.5 of Tarapoto-Yurimaguas road, 06°27’S 076°21’W, 600 m, 24 January 1987, S. Knapp & J. Mallet 8554 (F) ; San Martín. Tarapoto, near the airport. Rio Cumbasa. Secondary scrub, 06°31’S 076°22’W, 350 m, 8 June 1984, S. Knapp & J. Mallet 6488 (BH, USM) .

Cultivated collections:— National Collection Passiflora (UK) , J. Vanderplank; Nadines ( Germany), N.v. Rüschen; Passiflora collection Austria, M. Varga; Passiflorahoeve ( Netherlands), P. Moerman; Passifloratuin ( Netherlands), H.v. Aalst; Portland Botanical Gardens ( USA), D. Pogust; The Italian Collection ( Italy), M. Vecchia. Private collections: R. McPhail ( Netherlands), S. Berger ( Germany).

Discussion:— The new species belongs to Passiflora subg. Passiflora , supersect. Stipulata Feuillet & MacDougal (2003: 38) , within which it is placed under P. ser. Menispermifoliae Killip ex Cervi (1997: 84). Species belonging to this series are characterized by an apparent alikeness to Passiflora menispermifolia Kunth (1817: 137) , meaning that plants are pubescent to hirsute throughout; having conspicuous semi-ovate to subreniform stipules; petioles with 2 or more petiolar glands placed invariably along the length of the stalk; foliaceous bracts inserted 5 mm below the base flower; and a coronal structure containing 3 or more series of filaments (Cervi 1997, Feuillet & MacDougal 2003). Within this series, the new species belongs to a group of roughly ten species that are coarsely hirsute throughout (with the exception of the flower), featuring three-lobed leaves and petioles with 2–4 pairs of stipitate nectaries.

The new species was initially identified for Passiflora hastifolia . Both these species share greatly similar foliar shapes, with lobar sinuses that often reach 90 o or near; and stipules with entire, to partially entire margins. The upper foliar surface in the new species is glabrecent to glabrous with pubescence only on the under surface, whereas in P. hastifolia the foliar surface is pubescent to tomentose on both sides. The lobes for the new species are square-pyramidal in shape, without a distinct narrowing at the base; while in P. hastifolia the leaves are often markedly narrowed at the base giving it a distinct hastate leaf-shape (most apparent in juvenile foliage). Passiflora asprantha is most distinct however by its floral morphology, carrying pure white flowers that occasionally, albeit it faintly, have yellowish coronal apices. In contrast, the flowers of P. hastifolia are purple-lavender, with a dark purple corona that becomes gradually lighter towards the apex. Both species have a glabrous ovary, which marks it distinctly different from the pilose ovary seen in P. nephrodes . It is further distinct by its north Peruvian distribution, which is shared only with P. menispermifolia that, similar to P. hastifolia , carries purple-pink to lavender flowers, but also has markedly different foliar shapes.

Figures

FIGURE 1. Lankester Composite Dissection Plate (LCDP) of Passiflora asprantha. Featuring morphological detail of: A) habit; B1) stipule and petiolar nectaries; B2) the minute bracts below the flower; C) leaves, showing the distinct and consistent hastate shape of the foliage; C1) juvenile leaves maintaining the hastate shape; C2) the slightly peltate insertion of the petiole below the blade; D) Detail of the white flower; D1) a cultivated flower showing the slightly yellowish apices of the corona; D2) floral orientation showing the reflexed petals and sepals during anthesis. E1) Mature fruit; E2) detail of the seed. Compiled using photographs of J.R. Kuethe, Neil Rosser and Maurizio Vecchia.

FIGURE 3. Direct comparison between Passiflora asprantha (A, C, E) and P. hastifolia (B, D, F). Featuring the distinct differences in flower (A, B), leaf (C, D) and fruit (E, F). Taken from photographs by J.R. Kuethe (A, D, F), Cody Hinchliff (B), Neil Rosser (C) and Ochoa Jorge (E).