The host plants of the carpenter bee, cigarrón, Xylocopa brasilianorum L., whose flowers supply adult foods, nectar, and pollen, and whose woods are used as nesting sites are reported. More than ten years of observations and accumulated notes indicate that more than 284 dicotyledonous and one monocotyledonous species (male bamboo, Dendrocalamus strictus (Roxb.) Nees) are used for food. Of these 285 plants, 277 are reported for the first time for Puerto Rico. Thirteen species are used as nesting sites, with eight being first reports also. It is suggested that the carpenter bee inadvertently, directly or indirectly may be responsible for the pollination of 25 fruit and seed crops that are used as food by man in Puerto Rico.