定義： secondary vascular tissues with large amounts of softer storage cells (i.e. parenchyma) mixed with the wood or xylem cells. The stems of these plants are softer than the wood of trees we use for lumber.
定義： This organism produces this material or substance, either during its life or after death. A produces B if some process that occurs in A has output B.
定義： A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
