Phalaenopsis quadridentata M.Khanal & Kumar, 2025

Phalaenopsis quadridentata M.Khanal & Kumar , sp. nov. (Figs 1,2)

Type:— INDIA . Arunachal Pradesh: Lower Subansiri Potin , 1034 m, 2 Mar 2025, Khanal 2108 ( holotype: CAL) ; Khanal 2108 ( isotype: ARUN) .

Diagnosis: The new species is closely allied to Phalaenopsis mirabilis & Phalaenopsis putaoensis based on vegetative and floral morphology but the new species can be differentiated easily from both the species based on several morphological features ( Table 1).

Epiphytic, monopodial herbs up to 5 cm tall. Roots 3.0–6.0 × 0.2–0.3 cm, green to brown, laterally compressed, sparsely verrucose. Stem short, 1–3 mm long, appressed to the substrate, usually enclosed by 1–2 persistent sheaths at base. Leaves borne singly or rarely in a pair, 2.0–3.0 × 0.9–1.3 cm, oblong-elliptic, obtuse, entire, with a prominent midvein, green, succulent, petiole 1–2 mm long, glabrous. Inflorescence racemose, 2–4 cm long, erect, unbranched, laxly 1–4-flowered. Floral bracts 3–4 × 1–2 mm, ovate-triangular, entire, acute, greenish brown, turning to transparent white upon maturity, concave, glabrous, persistent. Flowers widely opening, resupinate; sepals and petals greenish, reflexed at maturity; column and spur greenish white; labellum white often with faint reddish blotches at base of lateral lobes; sub-globose dark brown-coloured glands placed laterally to the column adjacent to the lateral lobes of the labellum. Pedicel and ovary 1.0– 1.3 cm long, greenish. Dorsal sepal 4.0–4.5 × 2.0– 2.2 mm, elliptic, entire, obtuse, 3-veined, glabrous, concave apically; lateral sepals 5.0–5.2 × 3.0– 3.5 mm, ovate to broadly triangular, entire, acute, 3- veined, slightly concave, glabrous. Petals 4.0–4.3 × 1.3–1.5 mm, elliptic, entire, obtuse, 3-veined, glabrous. Labellum trilobed; midlobe cochleate, 6.0–6.2 × 3.0– 3.2 mm, with upper margin touching each other; lateral lobes 1.0– 1.2 mm long, triangular with a tooth on the margin near the middle of the length on either side, acute with converging spices, glandular pubescent; midlobe 5.0–5.3 × 3.0– 3.4 mm, ovate to elliptic, entire, obtuse; disc glandular pubescent, with a pair of calli at base, grooved towards the apex; spur emerging from the base of the labellum, conical, 3.5–4.0 mm long, entire, obtuse, inner surface densely pubescent; base of the disc adorned with 4 teeth-like appendages, acute, glandular pubescent. Column 1.9–2.2 mm long, parallel to the midlobe of labellum, glandular pubescent at base, column foot 3.0– 3.5 mm long, entirely adnate with spur; a pair of subglobose glands placed laterally to the column adjacent to the lateral lobes of the labellum. Rostellum triangular, beak like. Anther terminal, anther cap 1.0– 1.2 mm long, ovoid, entire, round, greenish. Pollinia 2, globose, yellowish, stipe spatulate, translucent. Fruits not seen. ( Fig. 1–2 View FIGURE 1 View FIGURE 2 ).

Etymology:— Referring to the presence of 4 tooth-like appendages at the junction of labellum and column.

Phenology:— Flowering: March–April; fruiting: not observed.

Distribution:— Known only from Potin, lower Subansiri district, Arunachal Pradesh, India [Endemic].

Habitat:— On trunks of Castanopsis indica , Liquidambar excelsa, Ficus sp. and other tall trees on roadsides and hill slopes. Other plants present in the area were Erythrina stricta , Duabanga grandiflora , Amomum sericium , Hedychium sp. and Nephrolepis sp. ( Fig. 2 View FIGURE 2 ).

Conservation status:— Known from just six flowering individuals at a site located next to a tribal village. The local people are dependent on the surrounding forests for their livelihood. The Area of Occupancy (Bachman & Moat 2012) is 4 km 2. Plants were not observed to set fruit and almost nothing is known about their biology. Based on this information, the species could be assessed as critically endangered. However, potentially suitable habitat is extensive, and the possibility that this species occurs in adjoining areas cannot be ruled out. Plants grow inconspicuously among epiphytic ferns and mosses and hence are likely to be overlooked. Accordingly, we suggest, this species is assessed as Endangered [EN B2a(iii)] ( IUCN Standards and Petitions Committee 2024). More species-specific surveys are needed to understand the distribution, population size and demography, and pollination biology of this species.