<prompt> Most common plant implicated in the causation of dermatitis isCotton fibresPoison ivyPahenium grassRagweed  <response>: Pahenium dermatitis is caused by dry powder of leaves and flowers and hair-like structures trichomes. Sesquiterpene lactones SQLs are the most impoant allergens responsible for ACD to pahenium. Ref Harrison20th edition pg 1234 