Gaultheria crassa, commonly known as the scarlet snowberry,[1] is a species of small shrub that belongs to the heath family Ericaceae.

The name crassa originates from the Latin term crassus,[2] meaning thick, fleshy, dense or fat which is related to the characteristics of its leaves.

It is abundant among subalpine and alpine scrub as well as among shrubland on the eastern side of the South Island mountain ranges.

It is common in Aoraki / Mount Cook National Park[9] and is most widespread in Canterbury alpine regions.

[5] Populations in the Craigieburn Range, Lake Lyndon, Cass and Otira Valley in Arthurs Pass National Park have been subject to studies.

[10] This species has a preference for rocky places and open scrub among the mountains of the South Island of New Zealand.

It is often an early coloniser of stable moraine sites where glacial debris has created an ideal habitat of loose rocks and low competition.

This differs from its close relative G. rupestris, which is more abundant on the wetter areas of the West Coast mountain ranges.

[13] This shows that areas where the species is found can have extreme seasonal variability in both rainfall and temperature.

Tiny clusters of Gaultheria crassa's creamy bell-shaped flowers appear from October to December.

[14] These small and numerous seeds are wind-dispersed,[3] a necessary requirement for plants in harsh moraine habitats where unstable rocks can often cause disturbances.

[10] The group is believed to have evolved less than 80 million years ago, meaning they arrived after the landmass split from the continent of Gondwana.