Lyallia

Lyallia is a genus of flowering plants belonging to the family Montiaceae (formerly Portulacaceae). These are small, cushion-forming plants endemic to subantarctic islands in the Southern Ocean, specifically the Crozet Islands, the Kerguelen Islands, and Heard Island.

Lyallia species are characterized by their compact, mat-forming growth habit which allows them to withstand the harsh conditions of their habitat, including strong winds, cold temperatures, and nutrient-poor soils. They are typically found in fellfields and other exposed, rocky areas.

The genus Lyallia currently comprises three recognized species:

• Lyallia kerguelensis Hook.f.
• Lyallia rossii Hook.f.
• Lyallia plumulosa Diels

The taxonomic history of Lyallia reflects the broader changes in the classification of the Portulacaceae family. With modern molecular phylogenetic studies, Lyallia has been placed within the Montiaceae.

These plants play an important ecological role in their limited geographic range, contributing to the overall biodiversity of these remote and fragile ecosystems. They are of interest to botanists studying plant adaptation to extreme environments.