Himalaya Mountains. If there is a natural wonder worthy of the title “monumental”, it is certainly these towering peaks. Home to some of the highest points on our planet, these rugged peaks are famous for the nearly insurmountable challenges faced by adventurers from around the world. Considering their altitude, it seems unlikely that there could be permanent life on these mountains.
However, this couldn’t be further from the truth. Among the sprawling bushes and tiny herbs, there is one of the most peculiar plants known to the world. To make things more interesting, it is a relative of rhubarb, a garden and pie crop grown in much more hospitable climates.
Meet the noble rhubarb, Rheum nobile. Growing at altitudes between 13,000 and 15,000 feet (4000–4800 m), this species is quite deserving of its exalted status. Crops grown at such altitudes face some serious challenges. Temperatures regularly drop below freezing and there is no shortage of harmful UV radiation.
As in most alpine regions, most plants cope with these conditions by growing prostrate on the ground and finding little shelter they can find behind rocks. Not Rheum nobile. This member of the buckwheat family can grow to a height of 6 feet, making it easily the tallest plant for miles.
The most striking feature of this plant is its large pyramidal shape with translucent bracts. These modified leaves do not contain chlorophyll and therefore do not serve as photosynthetic centers. Instead, these structures are there to protect and warm the plant. Hidden behind the bracts are the flowers.
If they are exposed to the elements, they will freeze or be fried by UV radiation. Instead, these ghostly bracts contain specialized pigments that filter out harmful UV wavelengths and create a microclimate favorable for flower and seed growth. In essence, the plant grows in its own greenhouse.
As a result, the temperature inside the plant can be up to 10 degrees higher than the ambient temperature outside. At such high altitudes, this is actually a boost to its reproductive efforts. An even greater challenge is that at this altitude, pollinators are often in short supply. Plants must do what they can to attract their attention. Rheum nobile not only offers a visual cue in stark contrast to its bleak surroundings, it also serves to chemically attract pollinators.
Rheum nobile has formed a mutualistic relationship with the fungus mosquito that lives at this altitude. The plant produces a unique chemical compound that attracts female mosquitoes. Females lay eggs in the growing seeds of plants, but in return they pollinate more flowers than they can parasitize. These creatures tried to achieve balance in these mountains. To be pollinated, fungus gnats have a warm place to raise their young, which is shielded from harmful outside ultraviolet radiation.