Common Thistle (Cirsium vulgare). Asteraceae. August 16, 2020 1500 × 1200 Common Thistle (Cirsium vulgare). Asteraceae. Non-native, invasive. Fields, roadsides. Throughout. Montauk, Aug 2019. Non-native, invasive. Fields, roadsides. Throughout. Montauk, New York, August 2019.