Meconopsis merakensis Tosh.Yoshida, Yangzom & D.G. Long var. merakensis , Sibbaldia

Meconopsis merakensis Tosh.Yoshida, Yangzom & D.G. Long var. merakensis, Sibbaldia View in CoL 14: 89. 2017 [“2016”]. Type: BHUTAN, Trashigang district, Merak region , 03.07.2014, 4290 m, R. Yangzom & C. Wangmo 730 (THIM!). FigS. 1 View Fig & 2 View Fig

Herbaceous, monocarpic, 30–60 cm tall, whole plant covered with brown or white patent spiny hairs throughout; stems 12–30 cm long, spreading, with 2–5 mm long bristles. Basal leaves many; petioles broadly linear, membranous, 2–8 cm long; lamina mostly strap-shaped or linear-oblong, margins entire or wavy, occasionally coarsely toothed, acute or rounded at apex, densely covered with patent spiny hairs on both surfaces. Inflorescence racemose, tip of elongate rachis often gradually narrowed and curved. Flowers 4–12, on 2–4 cm long pedicels, usually nodding, bowl-shaped, 2–6 cm across. Sepals 2 or 3, oblong, 1–1.6 cm long. Petals 4–6, broadly obovate-suborbicular, 2–4 cm long, margins entire, bluish or purplish. Stamens numerous; filaments filiform, 6–8 mm long, yellow. Ovary ovoid, densely bristly; style 1– 4 mm long; stigma 4–7-lobed, greenish yellow. Capsules sub-cylindrical, bristly, 3–3.5 cm long, with prominently thick conical base.

Flowering & fruiting: Flowering from July to August and fruiting from August to September.

Habitat: The plants occur on Northwest facing alpine meadows and rocky slopes in high altitude Himalaya, between 3800–4500 m. The species is very rare and occurs in the field with scattered populations confined to some isolated pockets in the Northwest regions of the Nagula lake area. The Monpa community of Tawang has strictly prohibited the collection of fuel wood, fodder and other forest resources from the Nagula Tso sacred landscape under their community customary laws.

Distribution: Eastern Bhutan and now in India.

Specimen examined: INDIA, Arunachal Pradesh, District Tawang, Nagula Tso N 27 ̊39'04.07" E 91 ̊51'48.95", 4200 m, 30.07.2018, K. S . Kanwal & M. Ori SERB / KSK/1203 About KSK ( ARUN, GBPI) .

Conservation notes: Meconopsis merakensis var. merakensis faces threats from livestock, mainly from trampling by yaks and horses, unregulated tourism, development works that result in the destruction and fragmentation of the species’ habitat. In the future, the species may face further threats due to climate change. Seven species of Meconopsis have shown an upward shift in mean elevation of 302.3 m between the pre 1970s (1922–1969) and the post 1970s (1970–2016) in the Himalaya–Hengduan Mountains region (He et al., 2019). Endemic and rare plant taxa, such as M. merakensis var. merakensis , with very small populations and special habitats, require specific conservation measures such as the development of an on-site Meconopsis garden for the germplasm conservation in the Tawang district.

Notes: The detailed analysis carried out here revealed that M. merakensis var. merakensis is close to M. prainiana Kingdon-Ward var. prainiana in having four-petalled flowers, hairy stems and in leaf structure but differs by its longer and sub-cylindrical capsules and stems less densely covered with spiny hairs ( Yoshida et al., 2017 [“2016”]). Meconopsis merakensis has two varieties, var. merakensis characterised by its bluish or purplish flowers, and M. merakensis var. albolutea Tosh.Yoshida, Yangzom & D.G.Long distinguished by its white or yellow flowers ( Yoshida et al., 2017). The latter variety is distributed in Bhutan and western Arunachal Pradesh, India.