Although the bamboo may not be nearly as imposing or sturdy as the pine, it too remains mostly green through the winter as segment upon segment reach out with abundance and stamina to withstand the cold. Unlike the pine, however, the stalk of the bamboo is hollow, which came to symbolize tolerance and open-mindedness. Furthermore, the flexibility and strength of the bamboo stalk also came to represent the human values of cultivation and integrity in which one yields but does not break. Along with the pine and the plum, the bamboo is a member of the “Three Friends of Winter (歲寒三友).” It is also one of the “Four Gentlemen (四君子)”, together with the plum, the orchid, and the chrysanthemum.