Philippines, Mindanao Island, Bukidnon Province, Mt. Pantaron Range, San Fernando, Barangay Magkalungay, Mt. Malimumu, 07 March 2021, Lagunday, NEL 013 (holotype PNH!, isotype CMUH!).

Philippines, Island of Mindanao, Province of Agusan, Cabadbaran (Mt. Urdaneta), September 1912, 13705 (ecopy of Isotype of Nepenthes surigaoensis Elmer, Leafl. Philipp. Bot. 8: 2785, 1915; verified by: J.C. Regalado, Jr., 1980).

RESULTS AND DISCUSSION

Nepenthes surigaoensis Elmer (1915: 2785).

Emended description: —Terrestrial shrub-climber, up to 8 m high scrambling on adjacent flora. Climbing stem internodes 3–4 cm; leaves green, 19 cm × ca. 3.5 cm, linear-lanceolate, sessile, 3–4 veins on each side run parallel to the midvein, pennate veins arising from the midvein at 45–80° angle, leaf base clasping up to ½ of the stem diameter becoming decurrent up to the entire internode, apex acute. Ground pitchers ellipsoidal to urceolate, up to 22 cm long × 14 cm at widest region; wings up to 1.5 cm with filaments up to 1.5 cm long run the entire pitcher anterior; pitcher exterior yellow green suffused and blotched with blood red subtended by uncoiled yellow-green glabrous tendrils ca. 43 cm long and 1.5 cm in diameter; pitcher interior yellow-green blotched with dark red; peristome ovate slightly tapering posteriorly giving a short neck, color variable from yellow-green suffused with red to entirely dark red; lid ovate, ca. 8 × 6 cm, dorsal and ventral surface with variable coloration from entirely olive green to suffused red. Aerial pitchers wholly infundibular, slightly inflated bottom ½, 19.5 cm long x up to ca. 6 cm at the widest region, subtended by coiled tendrils; pitcher exterior suffused red, pitcher interior waxy zone yellow-green blotched with dark red, digestive zone dark green; peristome ovate slightly tapers posteriorly giving a short neck, variable coloration from yellow-green suffused with blood red to entirely dark red, teeth triangular ca. 1 mm, with ridges elevated ca. 0.1 mm with ca. 1 mm space in between; lid ovate, up to ca. 8 × ca. 6 cm, dorsal surface with distinct paired elevated vein with short indumenta running up to half of the lid, up to 4 veins arise from base of the paired veins running the entire lid, up to 3 veins traverse the lid shallow depressed mid-region; lid ventral surface with small extrafloral nectar glands (ca. 0.1 mm) evenly distributed, central basal appendage or ridge absent; lid spur filiform, unbranched, up to 13 × 1 mm tapering to the slightly biforked. Female Inflorescence glabrous, 2-flowered partial peduncles sit on a ridge giving the rachis an angular appearance, rachis ca. 30 cm long, scape ca. 11.5 cm, ca. 7 mm in diameter; partial peduncles ca. 7 mm long, 2 mm in diameter; pedicels subtending the florets ca. 1 cm long, 1 mm in diameter; fruits ca. 1.3–2.5 cm; tetrapetalous, tepals narrow-ovate, 5 × 2 mm; seeds many, length ca. 1.5 cm x 1 mm. Male Inflorescence 2 flowered partial peduncles sit on a 35 cm long rachis, scape, yellow-green, ca. 11 cm long; partial peduncles sit on a ridge giving the rachis an angular appearance, 2 mm long, ca. 1 mm in diameter, with filiform process ca. 0.5 cm long arising near the base; pedicels subtending the florets, yellow-green to yellow to brownish, ca. 1 cm; tepals ovate-lanceolate, ca. 5 mm x 3 mm, concave, floral nectar glands ovate to narrow-ovate, ca. 0.8 × 0.1 mm, yellow-green suffused with red towards the margins; anther tubes ca. 3 mm long, 1 mm in diameter, suffused with pinkish red; florets faint yellow, 2 mm x 3 mm, theca ca. 20 centrally fixed recurved forming a head.

Taxonomic and ecological notes: — Nepenthes surigaoensis belongs to Nepenthes sect. Insignes or N. ventricosa Blanco (Blanco 1837: 807) as characterized characterized by its lack of petiole, broadly subcylindrical pitchers with broad peristome which is conspicuously toothed on its inner surface. It is easily mistaken for N. merrillian a due to striking similarities but can be delineated in having strongly decurrent leaf-to-stem attachment (N. merrilliana: obliquely decurrent up to 2/3 rd of the stem internode), subcylindrical aerial pitchers (vs. wholly infundibular). It thrives on gravel and clay-loam substrates at 700–1100 m asl in Talangisog, Eureka, Gingoog City, Misamis Oriental; Mt. Pantaron Range (Fig. 3), Mt. Limbawon, Tago Range (Fig. 4), Mt. Kiamo, in Bukidnon. Other noteworthy species thriving with N. surigaoensis includes N. cabanae Lagunday & Amoroso (2019: 39), N. manobo Lagunday, Acma, Cabana, Sabas & Amoroso (2017: 161), N. malimumuensis Lagunday, Acma, Cabana, Sabas & Amoroso (2017: 161), N. talaandig Gronemeyer, Coritico, Wistuba, Micheler, Marwinski, Gieray & Amoroso (2014: 292), and N. truncata Macfarlane. (1911: 209).