Exposure to the wind, significantly fluctuating temperatures, and frost (for snow does not stick to the mountain's vertical façades and peaks) all create harsh conditions for plants which must make use of the tiniest crack to take root.

Anchored in the rock by its long root, the Moss Campion protects itself against the wind and makes its own humus from the little decaying flowers from preceding years.
Silene acaulis © PNV / Patrick Folliet
Some ten types of saxifrage are found in the Vanoise. The most amazing insert their roots into tiny cracks. Their tough leaves often form a very thick and compact rosette that helps insulate them from the cold.
Saxifraga paniculata © PNV / Philippe Benoît
The combination of an alga and a microscopic mushroom, lichen is an organism capable of waiting weeks or even months for favourable conditions in which to grow. This enables it to spread over the entire surface of the world. Sixteen species have been counted at the summit of the Grande Casse, at an altitude of 3855 metres.
Lichen © PNV / Philippe Benoît