Cypripedium tibeticum
Cypripedium tibeticum is a species of orchid in section "Cypripedium" in the subsec. "Macrantha" It is native to Bhutan, Sikkim, and Western China (Gansu, Guizhou, Sichuan, Tibet, Yunnan). Description. 13-35 cm tall. Leaves 3, 7-15 × 3.3-7.2 cm, glabrous on both surfaces except towards the tips. Infloescence 1-flowered, produced usually before the leaves have fully developed; bract 5–10.5 cm long. Flower sub-nodding, very variable in colour; ovary glabrous or rarely slightly pubescent or papillose towards the apex, 2–3.2 cm long. Sepals 3–5.2 × 1.8-3 cm. Petals 3.6-6 × 1.4-2.5 cm . Labellum 3.5-6 cm long and wide, the margins of the mouth crimped all around, the outer surface usually wrinkled. Distribution. Sikkim, Bhutan and western China (Xizang, Yunnan, Sichuan and possibly S. Gansu); open montane meadows, margins of coniferous and mixed woodlands, open limestone ledges and screes; 2300-4600 m. Flowers from May to July. These plants usually form large clumps or colonies. Variation range. This species is notably variable across its distribution and sometimes it is hard to distinguish from other species such as "Cypripedium macranthos" or Cypripedium calcicola, the main distinction from "C. macranthos" are the darker flower  colour, especially when dried-pressed. Natural hybridisation. Seven specimens collected in southeastern Xizang may suggest natural hybridisation with "Cypripedium himalaicum". This orchid is also a parent of "Cypripedium" "× wenqingiae", an hybrid between "C. farreri" and "C. tibeticum". Cultivation. Together with its close relatives, this species replaces "C. macranthos" in southwestern China and the Himalayan re gion, and requires growing conditions similar to the latter in some respects. It differs in being more adapted to continental high mountain regions. Hence it needs some protection in winter, es pecially during frost-free periods, to maintain dormancy. Also, it should not receive  too much rain in winter. In summer it needs constant watering and a fresh and cool atmosphere while receiving full light (avoid the burning sun around noon). It can acclimatise in the garden, but will not grow into big clumps nor become as per sistent as C. macranthos. In the wild it is found growing in grassland on limestone and should have a compost with a pH between 6 and 7. It is not a beginner's species. Mixes A, B, C, D (made with coarse sand and some oyster shells), and J. Mix A: One part loam pellets, one  part Seramis (or comparable materials like pumice gravel), one part rotten wood, and one part coarse sand.