Passiflora mapiriensis Harms (1929: 810)

Kuethe, J. R., Balderrama, José A., Fuentes, Alfredo, Justiniano, Hermes & Lanas, Mattias, 2025, Resolving the Passiflora guentheri and P. mapiriensis enigma: identifying a third member of Passiflora sect. Simplicifoliae from the eastern Yungas, Bolivia, Phytotaxa 697 (2), pp. 166-176 : 170

Passiflora mapiriensis Harms (1929: 810) ( figure 1 , 2b–d–f , 4 )

Type:— BOLIVIA. La Paz: Mapiri region, San Carlos, 850 meters, 13 May 1927, fl., O. Buchtien 903 (holotype: B (destroyed). Lectotype: US 00115064, designated here).

Description. Plant a weakly tendrillate vine with branches 3–5 m long, essentially glabrous to very sparingly pubescent throughout (except for the ovary), with indument limited to younger stems. Stem subterete to slightly striate, slender, green throughout; stipules narrowly semi-lanceolate to narrowly reniform, 1–14 mm long, about 3–5 mm wide, longacuminate at apex turning into a mucro of 1.5–2 mm long, mucro slightly yellow at the very tip, semi-cordulate at base, soon deciduous; petioles 1.5–4.5 cm long, very slender, sparingly pubescent, caniculate, bearing 4–6 opposite to subopposite sessile glands about 0.6 mm in diameter, glands raised. Leaves broadly ovate to ovate oblong, 4.7–8.5 × 3.2–6.5 cm wide, acute to acuminate at apex, rounded or cuneate at base, entire throughout, quintupli veined, membranous, deep green above, dullish green below. Inflorescence in pairs, deep purple; peduncles 2–3 cm long, stout, erect; bracts borne about 7–9 mm below the base of the flower, lanceolate terminating into a mucro, 8–10 mm long, acuminate, membranous, green, mucro about 1–2 mm long. Flower showy, 6.5–8.7 cm in diameter, lavender to purple with a dark purple corona, sepals and petals reflexed at anthesis, scented; hypanthium deeply campanulate, 6–7 mm long, green to greenish yellow on the outside, green on the inside, sparingly pubescent; sepals narrowly oblong, 3.4– 3.8 cm long, 7–8 mm wide, obtuse at apex, slightly cucullate, without dorsal awn or keel, lavender to purple adaxially, greenish and pubescent abaxially, central vein pronounced by a dark shade of green; petals lanceolate-oblong, subequal to sepals, obtuse, purple, very thinly membranous; corona in 4–5 series, purple of various shades of intensity; outer series filiform, 2.2–2.9 cm long, very dark purple becoming lighter towards the apex terminating in a whitish tip, a single slightly paler band around 2/3 the length; inner series filiform to liguliform, 2.2–3.8 mm long, very dark purple, slightly length increasing towards center; operculum filamentose, erect and cleft around the androgynophore, 7.5–9 mm long, connate at base, dark purple becoming wine-red towards apex; limen closely surrounding base of gynophore, membranous; androgynophore greenish with dark purple speckles, about 18–22 mm tall; ovary ovoid, puberulent to pubescent; pollen greenish-yellow; anthers light greenish-yellow; stigma deep green throughout. Fruit not seen.

Distribution, habitat and conservation. Despite its name, the new populations seen for the species were all limited to the Carrasco National Park in Cochabamba department. The type locality, within the south-east of the Mapiri region, is greatly altered by unsustainable farming and mining, and no species from this alliance were seen within its proximities. In the Carrasco National Park, the species was found only nearby Siquena at elevations of around 950–1250 m. Here, the vegetation becomes distinct tropical rainforest, and the species was found growing in the undergrowth along slopes and small bush.

Evidently extremely rare, only three plants were seen within proximity, making it essentially a single population. This population covers an Extent Occurrence of about 0.150 km 2, with an AOO of <10 km 2, ranking it Critically Endangered in accordance with the IUCN (2022) guidelines.Were the original Mapiri location taken into this calculation the EOO would increase to 95 km 2, maintaining the CR rating in this category. The authors agree with this assessment, as either locality is under significant threat of forest clearance and unsustainable land-use resulted from mining. The current Carrasco population grows in very close proximity to an actively expanding hydroelectrical operation, marking the future of this population highly uncertain.

Notes. Killip (1938) did not write any taxonomic comments for Passiflora mapiriensis and treated it simply as a member of P. sect. Simplicifoliae . The type specimen that was designated for this species showed the broadly ovate shape of the leaf and a large open flower, although the stipules were absent in that specimen. Killip did include a description of the stipules meaning he must have had this information, possibly from the original manuscript by Harms (1929). The large population we found in the Carrasco National Park match the botanical descriptors provided by both Harms (1929) and Killip (1938) perfectly, additionally showing the deciduous nature of the narrow stipules explaining why they were absent in the type. The flower, showing remarkably similar colours to P. bangii (Masters 1907: 363) found also within the same habitat, is typical for the species of that alliance. The partially plicated opercular structure, emphasized for in P. guentheri , shows somewhat of a similar resemblance in this species, although the linear filaments are much more pronounced.

The differences between Passiflora mapiriensis and P. guentheri are best seen in the leaves and vegetative indument. P. mapiriensis appears to have very broadly ovate, membranous and “flat” leaves, whereas in P. guentheri the leaves are noticeably more elongate, coriaceous in texture and charismatically folded in a “V” shape. The stems of P. mapiriensis are green (opposed to purple) and are sparingly pubescent (vs. glaucous). The stipules, though deciduous, are very narrowly lanceolate to thinly reniform, while in P. guentheri the stipules are persistent, and semi-oblong to widely reniform. The flower, albeit it similar in general structure, is noticeably darker in the colour of the corona, with a much shorter inner coronal structure whereas in P. guentheri the corona appears to be more “stepped”, with the series gradually becoming longer towards the center of the flower. Lastly, just like Killip (1938) mentioned, the ovary of P. mapiriensis is distinctly pubescent, whereas in P. guentheri this organ is glabrous.

Figures

FIGURE 1. Botanical illustration showing Passiflora mapiriensis (A-F) and P. guentheri (G-L) in detail. Drawn from photographs taken in the field. P. mapiriensis: A) habit; B) petiolar nectaries; C) leaf outline; D) stipules and developing buds; E) bract; F) flower. P. guentheri: G) habit; H) petiolar nectaries; I) leaf outline; J) stipules; K) bract; L) flower. Drawn by Mattias Lanas.

FIGURE 2. Comparative rubric between P. guentheri (A,C,E) and P. mapiriensis (B,D,F). Note their subtle botanic differences including the shape and size of the stipules, floral structure, vegetative indument and foliar orientation. The stems and abaxial side of the leaves in P. mapiriensis are minutely pubescent (F), whereas in P. guentheri the stems and vegetative parts are glaucous (E). The number of petiolar nectaries or their respective location along the petiole is variable. Made with photographs taken by J.R. Kuethe (ACDEF) and Jose Balderrama (B). All photographs taken in situ.

FIGURE 4. Distribution map showing the three members of sect. Simplicifoliae distributed across Bolivia. Passiflora guentheri (green squares); Passiflora mapiriensis (blue triangles); Passiflora chaskajina (red circles). Shaded areas given for their possible distribution extents.