Rukkhasutta
“Cattārome, bhikkhave, rukkhā. Katame cattāro? Pheggu phegguparivāro, pheggu sāraparivāro, sāro phegguparivāro, sāro sāraparivāro— Ime kho, bhikkhave, cattāro rukkhā. Evamevaṁ kho, bhikkhave, cattāro rukkhūpamā puggalā santo saṁvijjamānā lokasmiṁ. Katame cattāro? Pheggu phegguparivāro, pheggu sāraparivāro, sāro phegguparivāro, sāro sāraparivāro.
Trees
“Mendicants, there are these four kinds of tree. What four? One is a softwood surrounded by softwoods, one is a softwood surrounded by hardwoods, one is a hardwood surrounded by softwoods, and one is a hardwood surrounded by hardwoods. These are the four kinds of tree. In the same way, these four individuals similar to trees are found in the world. What four? One is a softwood surrounded by softwoods, one is a softwood surrounded by hardwoods, one is a hardwood surrounded by softwoods, and one is a hardwood surrounded by hardwoods.