Gastrochilus dulongjiangensis Q. Liu & J. Y. Gao, 2018

Gastrochilus dulongjiangensis Q. Liu & J. Y. Gao View in CoL , sp. nov. ( Fig. 1 View FIGURE 1 )

Type: — China. Yunnan: Nujiang Prefecture, Dulongjiang Town , Montane rainforest, 1500 m, 19. Jan. 2017, Liu 415 (holotype: HITBC!) .

Diagnosis: — Gastrochilus dulongjiangensis is similar G. pseudodistichus and G. fuscopunctatus , but can be distinguished from them by having the orbicular epichile, hypochile as wide as epichile and fusiform pollinia.

Epiphytic herb, stem often branched, with purplish spots, pendulous and usually 15.0–30.0 cm tall, 1.5–2.0 mm in diameter. Leaves distichous, blade ovate, with purple-red spots on the abaxial leaf surface, 1.5–1.6 × 0.5–0.6 cm, apex acute and with 2–3 awns. Inflorescence sub-umbellate, 3–4 flowered; peduncle ca. 1.2 cm, upper part enlarged, lower part with 2 cupular sheaths with purple-red spots; floral bracts ovate-triangular, ca. 2.0 mm, membranous; pedicle and ovary yellow-green with purple-red spots, 5.9–7.2 mm. Flowers yellowish, with purplish marks or spots; the epichile yellow with sparsely purple spots and the hypochile white with purple maculae Dorsal sepal elliptic, 3.2–3.8 × 2.0– 2.7 mm, apex obtuse; lateral sepal similar in dorsal sepal, 3.4–4.3 × 2.2–2.6 mm, apex obtuse; petals ovate, 3.7–4.1 × 1.5–1.8 mm, apex obtuse. Lip with an epichile and a saccate hypochile; epichile orbicular, 2.6–3.0 × 2.9–3.1 mm, adaxial surface carinate and glabrous, entire, rounded at apex; hypochile nearly cupular, outside 3-ridges, margin with purple stripes, 4.0– 4.8 mm tall, 3.3–4.2 mm in diam. Column stout with purple spots, ca. 3.0 mm; anther cap galeate with recurved–acuminate apex, 1.8 × 1.5mm; pollinia 2, fusiform, ca. 0.6 mm in diam.; stipe elongate, ca. 1.4 mm; viscidium elliptic, thick and bilobed; rostellum bilobed with acuminated tip. Capsules cylindrical with 3 ridges, 26.5–28.2 × 8.8–10.6 mm.

Distribution:— Dulongjiang, Yunnan, China (close to the border with Myanmar).

Ecology:— Epiphytic on trees in the monsoon evergreen broad leaved forests on hills at 1450–1500 m elevation. Associated tree species include Cyclobalanopsis glauca ( Fagaceae ), Cyclobalanopsis lamellose ( Fagaceae ), Cyclobalanopsis kiukiangensis ( Fagaceae ), Manglietia fordiana ( Magnoliaceae ), Lithocarpus glaber ( Fagaceae ), Schima superba ( Theaceae ).

Phenology: — Gastrochilus dulongjiangensis was observed in flower from January to February, while the fruits were mature from April to May in the next year.

Etymology:— Named for Dulongjiang town in Nujiang Autonomous Prefecture, Yunnan Province, where the type was collected.

Additional specimens examined:— China. Yunnan: Nujiang Prefecture, Dulongjiang Town , Montane rainforest, 1450 m, 10 December 2016, Li YN-909 ( DS!) and 1500 m, 21. Feb. 2017, Liu 416 (Paratype, HITBC!)

Conservation status:— Until now, Gastrochilus dulongjiangensis is known from two sites, and just two populations were discovered in the field. However, the forests are well protected and linked to Dulongjiang on the northern side of Myanmar. Hence occurrence of more populations is highly likely in this vicinity. Therefore, it is premature to conduct a full conservation assessment based on the two known populations. We regard the species as Data Deficient (DD: IUCN 2012).

Taxonomic notes:— Morphologically, Gastrochilus dulongjiangensis is closed to G. fuscopunctatus (Hayata)

Hayata (1917: 78), G. pseudodistichus (King & Pantling) Schlechter (1913: 315) and G. kadooriei Kumar, S. W.Gale, Kocyan, G. A. Fisch. & Averyanov (2014: 93) for having pendulous stem, glabrous epichile and narrow or equal to the hypochile. However, the new species is characterized by having orbicular epichile and almost as wide as hypochile, fusiform pollinia. It differs from G. fuscopunctatus by having long and branched stems, ovate-lanceolate leaves and 3–4-flowed/ inflorescence (short and unbranched stem, falcate-oblong leaves and 1–2-flowered inflorescence in G. fuscopunctatus ; Fig. 2C View FIGURE 2 ); differs from G. pseudodistichus by having ovate leaves, non-reflexed perianth and ovate petals (lanceolate leaves, reflexed perianth and lancaolate petals in G. pseudodistichus ; Fig. 2B View FIGURE 2 ); differs from G. kadooriei by having pendulous stem, wider column (2.0 mm) and epichile with carinate (ascending stem, narrower column (1.6 mm) and epichile glabrous without carinate in G. kadooriei ; Fig. 2D View FIGURE 2 ).