Rhapidophyllum is a genus of just one species of fan palm, R. hystrix, native to the south-east United States.  It is an attractive, modest-sized but slow growing palm that forms suckers from the base and has a very spiny, short trunk.  It is generally considered to be the most cold-hardy of all palms (the main contender being Sabal minor), being used quite a bit in USDA zones 6 and 7 in the United States and tolerating temperatures below -23°C/-10°F once established.  It should be tried throughout the Pacific Northwest, including east of the Cascades with lots of summer water.  If it is given winter protection for its first several years, it will be much tougher and hardier once it is well established.  It likes summer heat and may sulk in a cool microclimate or near the coast.