Rheum nobile

Rheum nobile, the Noble rhubarb or Sikkim rhubarb is a giant herbaceous plant native to the Himalaya, from northeastern Afghanistan, east through northern Pakistan and India, Nepal, Sikkim (in India), Bhutan, and Tibet to Myanmar, occurring in the alpine zone at 4000–4800 m altitude.


It is an extraordinary species of rhubarb (genus Rheum). At 1–2 m tall, R. nobile towers above all the shrubs and low herbs in its habitat, and it is visible across valleys a mile away.
R. nobile is often called a glasshouse plant because of its outer curtain of translucent bracts which pass visible light, creating a greenhouse effect, while blocking ultraviolet radiation. These are important defenses against the increased UV-B exposure and extreme cold in its high altitude range.