| Baccharis angustifolia Michx. | map | images (1) (2) (3) |
| Baccharis glomeruliflora Pers. | map | |
| Baccharis halimifolia L. | map | images (1) (2) (3) |
| Bacopa caroliniana (Walt.) B.L. Robins. | map | |
| Bacopa innominata (G. Maza) Alain | map | |
| Bacopa monnieri (L.) Pennell | map | images (1) (2) (3) |
| Balduina atropurpurea Harper | map | |
| Balduina uniflora Nutt. | map | |
| Baptisia alba (L.) Vent. | map | images (1) (2) (3) |
| Baptisia albescens Small | map | |
| Baptisia bracteata Muhl. ex Ell. | map | images (1) (2) |
| Baptisia cinerea (Raf.) Fern. & Schub. | map | |
| Baptisia lanceolata (Walt.) Ell. | map | |
| Baptisia perfoliata (L.) R. Br. ex Ait. f. | map | |
| Baptisia tinctoria (L.) R. Br. ex Ait. f. | map | images (1) (2) (3) (4) (5) |
| Baptisia x microphylla Nutt. | map | |
| Barbarea verna (P. Mill.) Aschers. | map | |
| Barbarea vulgaris Ait. f. | map | |
| Bartonia paniculata (Michx.) Muhl. | map | |
| Bartonia verna (Michx.) Raf. ex Bart. | map | |
| Bartonia virginica (L.) B.S.P. | map | |
| Batis maritima L. | map | images (1) (2) (3) |
| Belamcanda chinensis (L.) DC. | map | |
| Berberis canadensis P. Mill. | map | |
| Berberis thunbergii DC. | map | |
| Berchemia scandens (Hill) K. Koch | map | images (1) (2) (3) |
| Berlandiera pumila (Michx.) Nutt. | map | images (1) (2) (3) (4) |
| Betula alleghaniensis Britt. | map | |
| Betula lenta L. | map | |
| Betula nigra L. | map | images (1) |
| Bidens aristosa (Michx.) Britt. | map | images (1) (2) |
| Bidens bipinnata L. | map | |
| Bidens coronata (L.) Britt. | map | |
| Bidens discoidea (Torr. & Gray) Britt. | map | |
| Bidens frondosa L. | map | |
| Bidens laevis (L.) B.S.P. | map | images (1) (2) |
| Bidens mitis (Michx.) Scherff | map | |
| Bidens pilosa L. | map | images (1) (2) |
| Bidens tripartita L. | map | |
| Bidens vulgata Greene | map | |
| Bigelowia nudata (Michx.) DC. | map | images (1) (2) (3) |
| Bignonia capreolata L. | map | images (1) (2) |
| Blephilia ciliata (L.) Benth. | map | |
| Boehmeria cylindrica (L.) Sw. | map | images (1) (2) |
| Boehmeria nivea (L.) Gaud. | map | |
| Boerhavia diffusa L. | map | |
| Boerhavia erecta L. | map | |
| Boltonia asteroides (L.) L'Her. | map | |
| Boltonia caroliniana (Walt.) Fern. | map | images (1) |
| Boltonia diffusa Ell. | map | |
| Borrichia frutescens (L.) DC. | map | images (1) (2) |
| Bothriochloa barbinodis (Lag.) Herter var. perforata (Trin ex Fourn.) Gould | map | |
| Botrychium biternatum (Sav.) Underwood | map | images (1) (2) |
| Botrychium dissectum Spreng. | map | |
| Botrychium jenmanii Underwood | map | |
| Botrychium lunarioides (Michx.) Sw. | map | images (1) |
| Botrychium virginianum (L.) Sw. | map | images (1) |
| Boykinia aconitifolia Nutt. | map | |
| Brachiaria platyphylla (Munro ex Wright) Nash | map | |
| Brachiaria ramosa (L.) Stapf. | map | |
| Brachiaria texana (Buckl.) S.T. Blake | map | |
| Brachyelytrum erectum (Schreb. ex Spreng.) Beauv. | map | images (1) (2) (3) |
| Brasenia schreberi J.F. Gmel. | map | images (1) (2) |
| Brassica juncea (L.) Czern. | map | |
| Brassica napus L. | map | images (1) (2) (3) |
| Brickellia eupatorioides (L.) Shinners | map | |
| Briza minor L. | map | images (1) (2) (3) |
| Bromus catharticus Vahl | map | images (1) (2) |
| Bromus commutatus Schrad. | map | |
| Bromus diandrus Roth | map | |
| Bromus hordeaceus L. | map | |
| Bromus japonicus Thunb. ex Murr. | map | |
| Bromus latiglumis (Shear) A.S. Hitchc. | map | |
| Bromus nottowayanus Fernald | map | |
| Bromus secalinus L. | map | images (1) (2) |
| Bromus tectorum L. | map | |
| Broussonetia papyrifera (L.) L'Her. ex Vent. | map | images (1) (2) (3) |
| Brunnichia ovata (Walt.) Shinners | map | |
| Buchnera americana L. | map | |
| Buddleja davidii Franch. | map | |
| Buddleja lindleyana Fortune ex Lindl. | map | images (1) |
| Buglossoides arvensis (L.) I.M. Johnston | map | images (1) |
| Bulbostylis barbata (Rottb.) C.B. Clarke | map | |
| Bulbostylis capillaris (L.) Kunthe ex C.B. Clarke | map | |
| Bulbostylis ciliatifolia (Ell.) Fern. var. ciliatifolia | map | |
| Bulbostylis ciliatifolia (Ell.) Fern. var. coarctata (Ell.) Kral | map | |
| Bulbostylis stenophylla (Ell.) C.B. Clarke | map | |
| Bulbostylis warei (Torr.) C.B. Clarke | map | |
| Burmannia biflora L. | map | |
| Burmannia capitata (J.F. Gmel.) Mart. | map | |