A bristlecone pine is one of three species of pine trees (family Pinaceae, genus Pinus, subsection Balfourianae). All three species are long-lived and highly resilient to harsh weather and bad soils. One of the three species, Pinus longaeva, is among the longest-lived life forms on Earth. The oldest Pinus longaeva is more than 5,000 years old, making it the oldest known individual of any species. Bristlecone pines grow in scattered subalpine groves at high altitude in arid regions of the Western United States. The name comes from the prickles on the female cones.