Hello, Last summer, I studied a forest in Hawai'i, but I have some problems of species determination... I would be glad if you could help me. You don't have to be a specialist of Hawai'i, because the first 6 pictures show alien species ! Thank you very much !
#3 might be Ricinus communis (Castor-oil plant, a common weed in tropical/subtropical regions) #4 looks like a Sambucus species (Elder)