Ranunculus sceleratus (cursed buttercup)

Baptisia tinctoria (horseflyweed)
Barbados
Barbarea intermedia
Barbarea vulgaris
Bartonia paniculata (twining screwstem)
Bartonia verna (white screwstem)
Bartonia virginica (yellow screwstem)
Beckmannia syzigachne (American sloughgrass)
Belarus
Belgium
Belize
Bellidiastrum michelii
Benin
Berberis
Berberis canadensis (American barberry)
Bergia texana (Texas bergia)
Bermuda
Berteroa incana
Berteroa incana (hoary alyssum)
Beta vulgaris var. altissima
Betula occidentalis (water birch)
Betula papyrifera (paper birch)
Betula pendula
Betula x sandbergii
Bhutan
Bidens beckii (Beck's water-marigold)
Bidens bidentoides (Delmarva beggarticks)
Bidens bipinnata
Bidens cernua

Image of Ranunculus sceleratus (cursed buttercup) 1
USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 2: 111.