Cushion plant

The typical form is a compact mass of closely spaced stems with minimal apical dominance that terminate in individual rosettes.

Underneath the living rosettes, the plants typically produce nonphotosynthetic material or allow previous leaves to die, creating an insulating effect.

[5] Cushion plants commonly grow in rapidly draining rocky or sandy soils in exposed and arid subalpine, alpine, arctic, subarctic or subantarctic feldmark habitats.

The plant actively grows only during the limited period when enough warmth and sunlight are available for photosynthesis, but may begin this cycle prior to the snow melting.

A small alpine forget-me-not may stand only inches above the ground, but its taproot can extend for a couple of feet below the soil surface.

The long taproot is necessary because of both the limited precipitation in many alpine and arctic environments, mostly as snowfall, and because of the rapid drainage of a newly formed and shallow soil.

So, by having tightly packed stems and foliage, cushion plants are able to convert and trap heat from sunlight, causing them to warm several degrees above the ambient air temperature and extend their short growing season.

About 338 species worldwide in 78 genera in areas ranging from Tasmania, New Zealand, and Tierra del Fuego to the arctic tundra of Svalbard have convergently evolved the same plant form in response to similar environmental conditions.