xanthium spinosum

annual arrangement asteraceae autumn background barb beautiful beauty biology blue botanical botany brown bud bur calyxes close closeup clotbur cocklebur common deadwood detail dried drug dry ecology fall family flora floret flower flowers foliage form grass hard head herbaceous large last natural nature plant red rough sand seed sepia shrub sky spinosum stalk stem steppe strumarium texture thorn tree weed wild withered woolgarie xanthium year