Coelogyne occultata

Coelogyne occultata Hook.f., Fl. Brit. India 5: 832 (1890) (syn: Coelogyne occultata var. uniflora N.P.Balakr.; Pleione occultata (Hook.f.) Kuntze);
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Sikkim to China (W. Yunnan): Assam, China South-Central, East Himalaya, Myanmar, Tibet as per POWO;
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Common name: Hidden Coelogyne
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Images and details from Jambey Tsering ji:

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References:
POWO  Catalogue of Life  Flowers of India