Passiflora kyathantha Kuethe & H.Garzón, 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 : 159-162

6. Passiflora kyathantha Kuethe & H.Garzón sp. nov. ( Figure 6 )

Type:— ECUADOR. Morona-Santiago: San Juan Bosco, Sendero al Cerro Pan de Azúcar , Potrero de don Ávila en río Chone , 03°09′30.2″S 78°34′23.6″W, 1861 msnm, 21 July 2024 (fl.), H. Garzón & A. Cárdenas 272 (holotype: HUTPL! (no barcode); isotype: HUTPL! (no barcode)) .

Diagnosis:— Passiflora kyathantha is similar to Passiflora putumayensis but differs in the shape (cupuliform vs. campanulate), size of the flowers (3.5–3.8 cm wide vs. 5.2–6.5 cm wide); and the colour and size of the inner corona (greenish white, 1-2 mm vs. stark yellow, 3-4 mm). They further differ in the shape (broadly ovate or ovate vs. lanceolate to narrow ovate) and texture (thick coriaceous vs. subcoriaceous or chartaceous) of the leaf.

Description:— Habit a small-size free-standing treelet up to 50–100 cm high and 4–7 cm DBH, essentially unbranched (monocaulous), glabrous to slightly glaucous throughout, except ovary. Trunk weakly wooded, stout, somewhat flaky, lenticellate. Younger stem stout, dark green, terete. Stipules subulate, very soon deciduous, ~1.0 mm long, dark green to brownish. Petioles stiff, 3.1–5.5 cm long, abaxially terete, longitudinally 2-ribbed and channelled adaxially (caniculate throughout), with one to three (one major and one or two minor) flattened gland(s) on each side of the midrib at base of the leaf blade; glands a dusty olive-green. Leaves simple, thick coriaceous, broadly ovate to ovate-elliptic, 25–45 cm long 13–18 cm wide, acuminate to acute at apex, rounded to broadly obtuse at base, margins entire, adaxial surface deep green, shiny, abaxial surface pale green to whitish-green, glabrous; pinnately veined, lateral veins 8–10, inter-secondaries present. Peduncles up to (2–) 5–7 cm long, sturdy to slightly wooded, subhorizontal to semi-pendent, once to twice (occasionally trice) dichotomous just above the middle, carrying 2–7 flowers per peduncle, articulated just below apex; pedicels 0.8–1.3 cm long, curved giving the flower an upwards orientation. Bracts minute, 0.5–1.2 mm if present, dark green to brownish, persistent. Flowers 3.5–3.8 cm in diameter during anthesis, the corolla always remains in a slightly campanulate orientation, white or whitish-green with yellow, sweetly scented; hypanthium cyathiform to tubular, 1.0– 1.3 cm deep, 0.4–0.6 wide at base, light green with darker green veins on the outside, whitish-yellow on the inside; sepals oblong to broadly ovate, 1.5–1.7 cm long, 0.8–0.9 cm wide, rounded and slightly concave at apex, greenish-white on the abaxial surface, white to white with green hues on adaxial surface, fleshy, ecorniculate; petals subequal to sepals, slightly wider, 1.4–1.6 cm long 0.6–0.8 cm wide, white on both surfaces, membranous; corona filaments arranged in two well-defined series, yellow with white becoming greenish-white at base; outer series slightly dolabriform, 10–12 mm long, white to whitish-green in the basal half, gradually becoming yellow in the upper half, the upper portion falcate, about 3.7–4.5 mm long, slightly thickened in lateral section; inner series minute, broadly linear, 2–3 mm long, greenish white to white gradually becoming greenish-yellow towards the tip with a yellow apex, radiate; operculum absent or reduced merely to a slightly swollen ring; androgynophore green to greenish-white, 1.6– 1.9 cm tall; staminal filaments green, 4–5 mm long; anthers 4–5 mm, white to whitish-yellow. Ovary ovoid, whitish to whitish-green, pubescent with whitish trichomes; styles 3–4 mm long, pale green to green; stigma 2.2–2.3 mm, whitish-green. Fruit pyriform to narrowly ovoid, triangular in lateral cross-section, 4.5–5.8 cm long, about 1.8–2.5 cm wide at its widest point, green to yellowish-green nearing to maturity, sparsely pubescent with whitish to brownish trichomes. Mature seeds not seen.

Phenology:— Passiflora kyathantha was seen with flowers during July-August and January, which implies a prolonged, but sporadic flowering pattern. Near fully ripe fruit were observed during the July collection.

Etymology:—The term “ kyathantha ” is derived from the Greek words “kyathos-” meaning “drinking glass” and “anthos” meaning “flower”. This was chosen in reference to its cup-shaped flowers with long hypanthium, resembling a drinking glass.

Distribution:— Passiflora kyathantha is found along the northwestern range of the Cordillera del Condór, with populations sighted in the provinces of Morona-Santiago and northern Zamora-Chinchipe. Notable populations were observed nearby San Juan Bosco along the trail to Cerro Pan de Azúcar, next to the Área de Conservación Municipal Siete Iglesias and the headwaters of the Río Piuntza, which are lower cloud forest reserves in the far southeast of Ecuador.The populations are seen at elevations between 1600 and 1900 m, where it grows near clearings, cattle pastures and forest edges of dense stratified, montane wet cloud forest. Treelets are found as small understory vegetation within small forest clearings providing them with partial sunlight from the forest edge, but have also been seen growing in grassy fields near to the forest edges.

Conservation status:—Using the four populations recorded gives an Extent of Occurrence (EOO) of 735–750 km 2, with an Area of Occupancy (AOO) of 12 km 2. Fruit and seedlings have been seen at two of these populations, confirming the presence of the effective pollinator. Habitat disturbance and clearing for grazing is seen throughout the region, causing instability and decline of suitable forest habitats. A conservation assessment of EN (Endangered) is proposed here in line with the IUCN (2022) criteria B1, B2ab, C1, C2ai and D.

Notes:— Passiflora kyathantha was first seen in 1972 by MacBryde 1000 (MO 3099506!) and mistakenly identified for P. putumayensis , most likely due to its small stature and single dichotomous flowers. In the Flora of Ecuador ( Holm-Nielsen et al. 1988), however, this same specimen was treated under the entry for “ Passiflora arborea ”, although the authors of that work admitted that the tiny size of the mature specimens was ill-fitting compared to the large Colombian trees that reach elevations more than 6 m. Recent collections by the fourth author helped to visualise this species further, which revealed several key characteristics that enabled the segregation of the P. putumayensis complex. The absence of an operculum makes for a unique trait among the members of P. supersect. Astrophea , allowing the hypanthium to be a mere open tube with the fleshy nectar glands freely exposed at the bottom of the tube. The shape of the hypanthium, forming a deeply cup-shaped to almost tubular structure, is seen only in P. gigantifolia , P. quelchii N.E. Br. (1901: 31) or P. bacabensis Mezzonato, Silva & Oliveira (2021: 79) , the latter two native to Guyana and central-eastern Brazil respectively. P. kyathantha is further remarkable for its small flowers, measuring no more than 4 cm in diameter what is unusual for the species of this group.

Being closely associated with Passiflora putumayensis , P. kyathantha is among the smallest members of P. subg. Astrophea normally not exceeding 75 cm in height. It differs from P. putumayensis by its small stature, the absence of an operculum (which is very pronounced in P. putumayensis ), and the texture of the leaves, which in P. kyathantha are glaucous, thick coriaceous and drying black when herbarized. In contrast, the leaves of P. putumayensis are glabrous, somewhat chartaceous but thin, and dry the usual brown to light brown in herbarium. The new species is further distinct by its unusually deep, cyathiform hypanthium, whereas in P. putumayensis the hypanthium is shallow campanulate.

Figures

FIGURE 6. A Lankester Composite Dissection Plate (LCDP) of Passiflora kyathantha sp.nov. Compiled with photographs taken by Henry Garzón-Suarez.