定義： a small cluster of elongated flexible outgrowths attached or close together at the base and free at the opposite ends especially; a growing bunch of grasses or close-set plants"
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)
