common beggarticks (bidens frondosa). cypselae closeup

asteraceae bidens frondosa compositae achene antrorsely barbed margin awn capitulum compressed cypsela head inflorescence receptacle retrorsely tuberculate common beggarticks bur marigold devil 039 bootjack pitchfork leafy weed sticktights tickseed sunflower frondosa cypselae closeup virtual herbarium belarus flora: focus-stacked closeups wild cultivated plants including flowers leaves fruits intended illustrations botanical manuals