What are some of the important plants and trees to Samoans and what were they used for? Objective Students will be able to: 1. Identify four native trees and two native plants 2. Learn about their uses. Background The use of medicinal plants dates to prehistoric times when ancient man found by trial and error that certain herbs and barks, when eaten, taken as an infusion, or applied externally, could alleviate some common ailments. When medicinal science began synthesizing organic and inorganic medicines in the nineteenth century, the use and reputation of herbal remedies began to decline. Syn Duration: 60 Minutes.