Nepenthes candalaga Lagunday & V.B.Amoroso, 2022

Lagunday, Noel E., Rosa, Sherolai Dela, Cleofei, Clint Michael B., Jr, Romeo Patano, Coritico, Fulgent P. & Amoroso, Victor B., 2022, Nepenthes candalaga (Nepenthaceae), a new species from eastern Mindanao, Philippines, Phytotaxa 554 (3), pp. 285-292 : 286-290

Nepenthes candalaga Lagunday & V.B.Amoroso , sp. nov. ( Figs. 2–3 )

Type: — PHILIPPINES. Mindanao: Davao de Oro, Maragusan Municipality, Mount Candalaga, Tropical Upper Montane Rainforest , 3 May 2021, Lagunday s.n. (holotype PNH!, isotype CMUH!) .

Diagnosis: — Nepenthes candalaga differs from N. justinae Gronemeyer, Wistuba, Mey & W.B.Amoroso (2016: 15) in having 2–3 longitudinal veins running in parallel with the midrib (vs. 3 longitudinal veins); an orbicular lid (cordate lid); non-bifid lid spur tip (bifid lid spur tip); triangular lid appendage (rounded appendage); banner-shaped wings just below the peristome covering only 1/6 th of the trap anterior becoming ridges towards the trap base (wings run down the front of the trap sometimes reduced to ridges); upper pitcher rim is absent and widest near the peristome (rim present and widest at the trap base) ( Table 1 ).

Description: —Terrestrial, scrambling on neighboring plants for support; Climbing stem terete, becoming reddish depending on sunlight exposure up to 8 m long and up to 5 mm in diameter, internodes are up to 5.3 cm, axillary buds conspicuous; leaves up to 14.5 cm long × 2.3–2.6 cm wide, more or less linear; petioles winged, reddish depending on sunlight exposure, up to 2.5 cm long × 7 mm wide; leaf base acuminate, leaf apex acute, margin irregularly recurved, with 3 longitudinal nerves running parallel with the midvein; pennate nerves at 30–60° from the midrib, numerous, moderately conspicuous; midrib reddish-brown and contrasting with green lamina. Upper pitcher widest just below the peristome, bottom half is slightly inflated becoming infundibular tapering toward the tendril, cylindrical mid forming a hip becoming infundibular towards the ovate opening; 10–15 cm long and up to 4 cm wide (widest point), waxy zone up to 56% of the pitcher length with ca. 0.2 × 0.2(–0.3) wax gland, digestive zone up to 44% of the pitcher length with ca. 0.4 × 0.5 mm digestive glands; banner shaped wings just below the peristome (1/6 of the trap anterior), up to 6 mm long × 5 mm wide, fringe filaments 2–3, 4.0– 4.7 mm long and 1–2 mm apart; mouth ovate tapering posteriorly to form a distinct vertically/slightly anteriorly inclined neck; peristome slightly flattened up to 3 mm wide, densely lined with ribs 0.5‒0.8 mm apart having small conspicuous short teeth-like projections with proximally sunken nectar glands in the semilunar depressions between ribs with canals emptying into the inner pitcher wall; spur is filiform, pubescent, unbranched, 1.0– 1.1 cm long and up to 0.5 mm in diameter; lid orbicular, 2.3–3.7 cm long × 2.7–4.2 cm wide, apex notched, base cordate, lid appendage inverted fin-shaped, apex pointed towards the peristome, 3.0– 3.5 mm at the base up to 3 mm long, nectar glands that are 0.1 × 0.1 mm are evenly distributed in the lower lid and appendage; tendrils coiling, up to 27 cm long and up to 5 mm in diameter. Color of living plants is much suffused with red depending on sunlight exposure. Peristome of upper pitchers greenish-yellow with narrow bands of maroon red. Pitchers marbled with red flecks towards mouth, becoming greenish at base. Pitcher interiors are creamy-yellow. Lid adaxial marbled red throughout depending on sunlight exposure. Lower/intermediate pitcher leaves were not observed during the time of collection. The female inflorescence is a panicle, pubescent except for the scape which is 16.5‒24.5 cm long scape up to 2–4 mm in diameter and an additional of up to 10 cm rachis. The partial peduncles are two 2-flowered, 6‒7 mm long and 1 mm in diameter. The pedicels are up to 9 mm long and up to 1 mm in diameter bearing tetramerous narrow ovate petals that are 6‒7 mm long and 3.5‒4.0 mm wide with huge round (ca. 3 × 3 mm) to elongated (ca. 1.25‒2.50 × 1‒3 mm) nectar glands becoming smaller towards the tepal apex in the upper surface. The capsule bearing the seeds are 2.2‒3.2 cm long and ca. 5 mm wide. The seeds have filiform extensions that are unequal in length ranging from 5.5‒7.0 mm on either sides, seed body is 1‒2 mm × 0.8‒1.0 mm, total seed length is 1.2‒1.6 cm long. Male inflorescence were not observed during the time of collection.

Etymology: —The specific epithet is a noun apposition. It signals the type locality of the species, Mt. Candalaga in Maragusan, Davao de Oro, eastern Mindanao, Philippines.

Distribution and ecology: —Populations of Nepenthes candalaga were observed only in the tropical upper montane rainforest of Mt. Candalaga at ca. 1800–2100 m a.s.l., scrambling on tree branches up to 10 m high and on Oleandra sp. and is recorded nowhere else. The mountain is tropical lowland evergreen rainforest (TLERF) at 800– 1000 m asl; tropical lower montane rainforest (TLMRF) at 1100–1800 m a.s.l. and tropical upper montane rainforest (TUMRF) at 1900–2100 m a.s.l.

Noteworthy flora observed in the site were Amylotheca cleofei Tandang, Galindon & A.S. Rob. (in Tandang et al. 2021: 114) and Nepenthes nebularum Mansell & Suarez in Mansell & Suarez (2016: 133) which can easily be recognized in the field in having cylindrical pitchers and broad leaves. The later was recorded in Mt. Mayo, Tarragona, Mati ( Mansell & Suarez 2016) and the former in Mt. Hamiguitan Range Wildlife Sanctuary, Davao Oriental ( Tandang et al. 2021). A. cleofei was observed along the river trails while N. nebularum populations were observed in the TLMRF and TUMRF (1700–1900 m asl) epiphytic on tree branches 10–15 m high.

Taxonomic notes: — Nepenthes candalaga morphologically falls under Nepenthes sect. Alata Blanco (1837: 805) displaying winged petioles and lids with basal ridges producing appendages.

Conservation status: — Nepenthes candalaga is assessed here as Critically Endangered (CR] based on the criterion B1ab(i) of IUCN (2022). The extent of occurrence (EOO) is less than 10 km 2. The species suffers the habitat loss because of the deforestation and typhoons as part of the mountain was significantly damaged by Typhoon Pablo in 2012. The species is known only from the Mt. Candalaga and is likely to be endemic to the mountain, which faces threats of deforestation and habitat loss without legislative protection.

Figures

FIGURE 2. Nepenthes candalaga. A) Aerial pitcher lateral view, B) lid adaxial, C) lid abaxial showing lid spur, D) seed, E) tepal showing floral nectar glands, F) dehisced capsule, G) female flower, H) lid spur, I) close up of the lid appendage, J) close up of lid nectar glands, K) close up of the peristome teeth-like projections and nectar glands in the inner margin, L) aerial pitcher anterior view, M) close up of the aerial pitcher wings, N) pitcher interior showing wax and digestive glands, O) climbing stem with infructescence and female flowers, P) leaf lamina showing longitudinal nerves. Scale bars: A, O = 5 cm; B, C = 2 cm; D = 1 cm; E, G, H = 5 mm; M = 1 cm. Illustration by S. dela Rosa.

FIGURE 3. General morphological details of Nepenthes candalaga. A) habit with aerial pitchers,B) infructescence with dehisced capsules, C) leaf lamina showing winged petioles, D) lateral view of aerial pitchers, E) lateral view of aerial pitchers, F) aerial pitcher long section, G) close up of dehiscing capsules, H) seed, I) adaxial and abaxial surface of the lid, J) lid spur, K) lid appendage, L) peristome showing teeth and nectar glands, M) waxy zone, N) digestive zone showing digestive glands, O) aerial pitcher wings. Scale bars: B, C, D, E, F; I = 1 cm; G, H, J, K, L, M, N, O = 1 mm. Photographs by N.E. Lagunday.