Nepenthes higaonon Lagunday & V.B.Amoroso, 2025

Nepenthes higaonon Lagunday & V.B.Amoroso View in CoL sp. nov.

Type: — PHILIPPINES. Mindanao Island, Misamis Oriental, Gingoog City, Barangay Eureka, Talangisog, 22 July 2021, Lagunday NEL 023 (holotype PNH!, isotype CMUH!).

Diagnosis: — Nepenthes higaonon differs from N. viridis in having a non-decurrent leaf-to-stem attachment (vs. slightly decurrent), rounded leaf apex (vs. acute), 3 longitudinal veins are present on either side of the midrib (vs. 1–2), monomorphic pitchers (vs. dimorphic); aerial pitchers cylindrical upper 1/3 rd (vs. infundibular upper 1/3 rd), aerial pitcher lid flattened, ovate, angled up to 90° completely exposing the opening (vs. domed, oval to cordate, angled up to ca. 60 ° covering the opening), aerial pitcher peristome anterior with shallow depression (vs. often raised); inflorescence 1-flowered (vs. 2-flowered), and in having climbing stems up to ca. 10 m (vs. up to ca. 4 m) ( Table 1).

Description ( Figs. 2 View FIGURE 2 and 3 View FIGURE 3 ): —Terrestrial shrub-climber, 5–10 m tall, internodes 3–4.5 cm, stems terete, pitchers monomorphic. Leaves green, petiolate 2.0– 2.5 cm long, 1.0– 1.5 cm wide, up to ca. 23 × 4 cm, green, glabrous, with 3 veins on each side running parallel to the midvein, linear to spathulate, clasping up to ½ of the stem diameter, base obtuse, apex rounded. Aerial pitchers entirely green, glabrous, ca. 22 × 5 cm interior waxy zone creamy white, digestive zone green, inflated bottom ½ becoming cylindrical towards the orbicular opening; peristome entirely yellow-green to green, recurved towards the exterior wall giving a cylindrical appearance, anterior shallowly depressed, posterior slightly elevated, teeth inconspicuous, neck and neck teeth absent; lid entirely yellow-green to green, ovate, ca. 5 × 4 cm, angled up to 90° completely exposing the opening; central basal appendage triangular; lid spur filiform and unbranched up to ca. 1 cm long and 1 mm in diameter. Female inflorescence 1-flowered pedicels sit on up to ca. 31 cm long rachis, scape up to ca. 22 cm long, ca. 1 cm in diameter, pedicels sit on a rid giving the rachis an angular appearance; pedicels holding the florets up to ca. 3 cm long, ca. 1 mm in diameter, fruits up to ca. 1.5 cm long, ca. 9 mm in diameter. Male inflorescence was not observed during sampling.

Etymology: —The specific epithet denotes the indigenous cultural group in the site.

Habitat and ditribution: — Nepenthes higaonon grows on gravel substrates at 700–800 m a.s.l. at Talangisog Viewpoint and Forest Park, Eureka, Gingoog, Misamis Oriental. Other noteworthy species thriving with N. higaonon includes N. cabanae Lagunday & Amoroso (2019: 39) , N. surigaoensis Elmer (1915: 2785) , N. manobo Lagunday, Acma, Cabana, Sabas & Amoroso (2017: 161) , N. talaandig Gronem., Coritico, Wistuba, Micheler, Marwinski, Gieray & Amoroso (2014: 292) , and N. truncata Macfarl. (1911: 209) .

Conservation status: — Nepenthes higaonon is assessed as Critically Endangered [CR] according to the IUCN (2025) criterion B1ab (i). Extent of occurrence estimated to be less than 10 km 2. Occurring at 700–800 m a.s.l. with an estimated number of 20 mature individuals threatened by shifting cultivation. Known only from the type locality and probably site endemic to Mt. Talangisog, Eureka, Gingoog, Misamis Oriental.

Taxonomic notes: —The species described in this work morphologically falls under Nepenthes alata Blanco ( Blanco 1837) group characterized in Cheek & Jebb (2013b). This discovery increases the Mindanao Nepenthes from 35 ( Lagunday et al. 2024) to 36 species.

Nepenthes higaonon View in CoL is also similar to N. alata Blanco (1837: 805) View in CoL in having monomorphic pitchers (vs. dimorphic), aerial pitchers with orbicular slightly tapering posteriorly forming a short neck (vs. distinctly narrow ovate forming a long neck), lids angled up to 85–90° angle fully exposing the pitcher opening (vs. angled up to ca. 45° partially exposing the pitcher opening), aerial pitchers without wings (vs. aerial pitcher sometimes winged).

Key to Nepenthes species occurring in Talangisog, Barangay Eureka, Gingoog City, Misamis Oriental: —It follows:

1a. Leaves sessile .....................................................................................................................................................................................2

1b. Leaves petiolate..................................................................................................................................................................................3

2a. leaf attachment to stem decurrent up to the entire internode....................................................................................... N. surigaoensis View in CoL

2b. leaf attachment to stem decurrent up to 1/3 rd of the internode ...........................................................................................................4

3a. leaves broad, triangular to rectangular .............................................................................................................................. N. truncata View in CoL

3b. leaves narrow, linear...........................................................................................................................................................................5

4a. leaf attachment to stem unequally decurrent..................................................................................................................... N. cabanae View in CoL

4b. leaf attachment to stem non-decurrent ............................................................................................................................... N. manobo View in CoL

5a. pitcher leaves dimorphic; lid partially exposing the pitcher opening............................................................................... N. talaandig View in CoL

5b. pitcher leaves monomorphic; lid fully exposing the pitcher opening .............................................................................. N. higaonon View in CoL