.
| Genus | |
|---|---|
|   | Babiana Ker Gawl. | 
|   | Baccaurea Lour. | 
| Bactris Jacq. ex Scop. | |
| Badula Juss. | |
|   | Baeometra Salisb. ex Endl. | 
| Baeriopsis J.T.Howell | |
|   | Balanophora J.R.Forst. & G.Forst. | 
| Baliospermum Blume | |
|   | Ballota L. | 
| Baloghia Endl. | |
|   | Banksia L.f. | 
|   | Baptisia Vent. | 
|   | Barbacenia Vand. | 
| Barbaceniopsis L.B.Sm. | |
|   | Barbarea Scop. | 
|   | Barclaya Wall. | 
| Barfussia Manzan. & W.Till | |
| Barkleyanthus H.Rob. & Brettell | |
|   | Barleria L. | 
|   | Barnardia Lindl. | 
| Barneoudia Gay | |
|   | Barringtonia J.R.Forst. & G.Forst. | 
|   | Bartonia Muhl. ex Willd. | 
|   | Bassecoia B.L.Burtt | 
|   | Bauhinia B.Heyne ex Wight & Arn. | 
| Bdallophytum Eichler | |
| Beaucarnea Lem. | |
| Beauprea Brongn. & Gris | |
| Beaupreopsis Virot | |
| Bedfordia DC. | |
|   | Beesia Balf.f. & W.W.Sm. | 
| Behnia Didr. | |
|   | Bejaria Mutis | 
|   | Bellendena R.Br. | 
|   | Bellevalia Lapeyr. | 
| Belosynapsis Hassk. | |
|   | Benthamiella Speg. | 
|   | Berberidopsis Hook.f. | 
|   | Berberis L. | 
| Bergeranthus Schwantes | |
| Bergerocactus Britton & Rose | |
|   | Berlinia Sol. ex Hook.f. & Benth. | 
|   | Berteroa DC. | 
|   | Berzelia Brongn. | 
|  | Beschorneria Kunth | 
|  | Besleria Plum. ex L. | 
| Bessera Schult.f. | |
| Bethencourtia Choisy | |
|   | Betula L. | 
|   | Biarum Schott | 
|   | Bidens L. | 
|   | Bignonia L. | 
|   | Billardiera Sm. | 
|   | Billbergia Thunb. | 
| Biophytum DC. | |
|   | Bistorta (L.) Scop. | 
|   | Bituminaria Heist. ex Fabr. | 
| Blachia Baill. | |
|   | Blackstonia Huds. | 
|   | Blakea P.Browne | 
|   | Blancoa Lindl. | 
|   | Blandfordia Sm. | 
| Bleasdalea F.Muell. ex Domin | |
|   | Blechnum L. | 
| Blennosperma Less. | |
|   | Blepharipappus Hook. | 
|   | Blephilia (L.) Raf. | 
| Bloomeria Kellogg | |
|   | Blossfeldia Werderm. | 
|   | Bobartia L. | 
| Boechera Á.Löve & D.Löve | |
|   | Boenninghausenia Rchb. | 
|   | Boesenbergia Kuntze | 
| Bolandra Gray | |
|   | Bomarea Mirb. | 
|   | Bonamia Thouars | 
| Bonellia | |
|   | Boophone Herb. | 
|   | Boopis Juss. | 
| Borodinia Busch | |
|   | Boronia Sm. | 
|   | Boswellia Roxb. ex Colebr. | 
|   | Botrychium Sw. | 
|   | Boucerosia Wight & Arn. | 
|   | Bourreria P.Browne | 
| Bouteloua Bouteloua | |
|   | Bouvardia Salisb. | 
|   | Bowiea Harv. ex Hook.f. | 
|   | Bowkeria Harv. | 
| Boykinia Nutt. | |
| Brabejum L. | |
| Brachycereus Britton & Rose | |
|   | Brachyclados D.Don | 
| Brachyglottis J.R.Forst. & G.Forst. | |
|   | Brachyotum (DC.) Triana | 
|   | Brachytome Hook.f. | 
|   | Brandisia Hook.f. & Thomson | 
|   | Brasenia Schreb. | 
|   | Brasilicereus Backeb. | 
| Brasiliopuntia (K. Schum.) A. Berger | |
|   | Brassica L. | 
| Braunsia Schwantes | |
|   | Brefeldia Rostaf. | 
|  | Brexia Noronha ex Thouars | 
| Brianhuntleya Chess. et al. | |
|   | Brighamia A.Gray | 
|   | Brimeura Salisb. | 
|   | Brocchinia Schult. & Schult.f. in J.J.Roemer & J.A.Schultes | 
| Brodiaea Sm. | |
|   | Bromelia L. | 
|   | Bromus L. | 
|   | Broussonetia Ortega | 
|   | Browallia L. | 
|   | Brownea Jacq. | 
|   | Browneopsis Huber | 
|   | Browningia Britton & Rose | 
|   | Brugmansia Pers. | 
|   | Brunfelsia L. | 
| Brunia L. | |
|   | Brunnera Steven | 
|   | Brunonia R.Br. | 
|   | Brunsvigia Heist. | 
| Bryocarpum Hook. f. & Thomson | |
|   | Bucephalandra Schott | 
|   | Buchnera L. | 
| Buckinghamia F.Muell. | |
| Bucklandiella Roiv. | |
|   | Buddleja L. | 
|   | Bufonia Sauvage | 
|   | Buglossoides Moench | 
|   | Bukiniczia Lincz. | 
|   | Buphthalmum Mill. | 
|   | Bupleurum L. | 
|   | Burmannia L. |