What is "lyallia"

Lyallia kerguelensis, commonly called the lyallia cushion (coussin de lyallia in French), is a species of flowering cushion plant in the monotypic genus Lyallia in the Montiaceae family. It is sometimes placed in the Hectorellaceae or the Portulacaceae. The generic name honours British botanist and naval officer David Lyall who served as assistant surgeon on HMS Terror on the Antarctic exploring expedition led by James Clark Ross from 1839 to 1843. Lyall was a friend and colleague of describer Joseph Dalton Hooker on the expedition when the type material was collected. The specific epithet refers to the type locality.