Which one is the most cold-hardy palms in the world, Halimodendron or Rhapidophyllum?
Halimodendron: Halimodendron is a monotypic genus of legume containing the single species Halimodendron halodendron, which is known by several common names, including common salt tree and Russian salt tree. Rhapidophyllum: Rhapidophyllum hystrix, the needle palm, is a palm, the sole member of the genus Rhapidophyllum. Rhapidophyllum:  It is one of the most cold-hardy palms in the world, and can be found growing in several areas with warm temperate climates.
Rhapidophyllum hystrix