The term TREES WITH POISONOUS SEEDS can be summarized as five letter word UUUUU. There are many species of trees that have poisonous seeds, such as the Manchineel tree, which is native to the Caribbean and parts of Central and South America. The tree produces a sap that can cause severe skin irritation and blindness if it comes into contact with the eyes. The seeds of the tree are also highly toxic and can cause vomiting, diarrhea, and even death if ingested.