Gastrodia kachinensis X.H.Jin & L.A.Ye

Aung, Ye Lwin & Jin, Xiaohua, 2018, Gastrodia kachinensis (Orchidaceae), a new species from Myanmar, PhytoKeys 94, pp. 23-29 : 24-27

Gastrodia kachinensis X.H.Jin & L.A.Ye Figures 1 , 2 , 3

Diagnosis.

Gastrodia kachinensis is similar to G. gracilis , but it can be easily distinguished from the latter by having perianth tube with punctate outer surface, verrucose outer surface of sepal lobe, orbicular petals, ovate-elliptic lip with truncate apex and auriculate-clawed base, glabrous lip with a pair of twin protuberance-like lamellae only at apex and column with a pair of blade-like lateral wings and acute stelidia at apex.

Type.

MYANMAR. Kachin State: Putao Township, Hponkanrazi Wildlife Sanctuary , subtropical, evergreen, broad-leaved forest, 1400 m in elevation, 19 May 2017, Xiaohua Jin et al, PT -6897 (Putao expedition team 6897) (Holotype, PE!) .

Description.

Terrestrial, fully mycoheterotrophic, leafless herb. Rhizome tuberous, vertical, subterete, 10-14 cm long, ca. 1 cm thick, greyish brown, covered with membranous scales. Stem erect and slender, ca. 30-40 cm long, 0.6 cm thick, distantly noded and sheathed. Raceme laxly 8-10-flowered, peduncle 10-30 cm long, ca. 0.5 cm in diameter, floral bracts minute, erect, lanceolate-ovate, dark brown, acute apex, 6 × 1.5 mm. Pedicel and ovary ca. 1 cm long, pedicel slightly curved, ovary ca. 2.5 mm in diameter. Flowers urceolate, resupinate, bending downwards, dark yellowish brown, ca. 1.3 cm long, 0.8 cm in diameter; sepals connate, forming a tube, tubular part ca. 1 cm long, outer surface punctate, trilobed at apex, sepal lobes ovate, 0.3 × 0.3 cm, outer surfaces verrucose; petals attached to sepal tube, orbicular, 0.2 × 0.2 cm; lip adnate to column foot, orange-yellow towards apex and pale greenish white along each lateral margin, ovate-elliptic, 0.7 × 0.4 cm, margin entire, apex truncate, base auriculate-clawed, two light yellow sub-globose calli at claw, adaxial surface of lip glabrous, with a pair of twin protuberance-like lamellae only at apex, lamellae ca. 1 mm tall; column straight, as long as lip, ca. 0.6 cm long excluding column foot, with a pair of blade-like lateral wings towards apex, stelidia acute at apex; column foot distinct; stigma distinct, near base of column, rounded, ca. 1.5 mm in diameter.

Etymology.

The new species is named after Kachin State, the northernmost state of Myanmar in which it was discovered in a vast area of primitive montane forest.

Distribution and habitat.

Gastrodia kachinensis is a terrestrial mycoheterotrophic species that grows in broad-leaved, evergreen forest at 1400 m in elevation. Gastrodia kachinensis is only known from the type locality.

Conservation status.

Endangered (EN). Gastrodia kachinensis was collected in the lowland forest of Hponkanrazi Wildlife Sanctuary, Putao, Northern Myanmar. Until now, only one population, consisting of ca. 10 individuals, has been discovered in the reserve (2704 km2). As the lowland forest is under direct threat from slash-and-burn agriculture, the species is here assigned a status of Endangered (EN) according to the guidelines for using the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Subcommittee 2017).

Key to Gastrodia kachinensis and G. gracilis

1	Perianth tube outer surface punctate; sepal lobes outer surface verrucose; petals orbicular; lip ovate-elliptic, margin entire, apex truncate, base auriculate-clawed, adaxial surface glabrous, with a pair of twin protuberance-like lamellae only at apex; column with a pair of blade-like lateral wings, stelidia acute at apex	Gastrodia kachinensis
-	Perianth tube outer surface smooth; sepal lobes outer surface smooth; petals ovate; lip ovate-triangular, margin undulate, apex obtuse, base truncate-clawed, adaxial surface tomentose, with a pair of longitudinal lamellae which are distinctly crested only at apex; column with a pair of semilunar lateral wings, stelidia acuminate at apex	Gastrodia gracilis

Figures

Figure 1. Gastrodia kachinensis X. H. Jin & L. A. Ye. A Rhizome B Inflorescence C Longitudinal section of sepal tube, showing two petals D Front view of column and lip, showing the stigma area with sectile pollinia E Lateral view of column and hypochile, showing a pair of sub-globose calli at lip hypochile F Lip epichile, showing a pair of twin protuberance-like lamellae at its apex. Illustration by Yunxi Zhu.

Figure 2. Habit of Gastrodia kachinensis. Photographed by X. H. Jin.

Figure 3. Gastrodia kachinensis X. H. Jin & L. A. Ye. A Inflorescence B Longitudinal section of sepal tube, showing two petals C Front view of column and lip, showing the stigma area with sectile pollinia D Sepal tube, lip, lateral view of column and the base of lip, showing a pair of sub-globose calli at lip hypochile E Rhizome. Photographed by X. H. Jin.