welted thistle: European biennial introduced in North America having flower heads in crowded clusters at ends of branches
thistle: any of numerous plants of the family Compositae and especially of the genera Carduus and Cirsium and Onopordum having prickly-edged leaves
host: a person who invites guests to a social event (such as a party in his or her own home) and who is responsible for them while they are there