| Sabal minor (Jacq.) Pers. | map | images (1) |
| Sabal palmetto (Walt.) Lodd. ex J.A. & J.H. Schultes | map | images (1) (2) |
| Sabatia angularis (L.) Pursh | map | |
| Sabatia bartramii Wilbur | map | |
| Sabatia brachiata Ell. | map | |
| Sabatia brevifolia Raf. | map | images (1) (2) |
| Sabatia calycina (Lam.) Heller | map | |
| Sabatia campanulata (L.) Torr. | map | |
| Sabatia difformis (L.) Druce | map | |
| Sabatia dodecandra (L.) B.S.P. var. dodecandra | map | |
| Sabatia dodecandra (L.) B.S.P. var. foliosa (Fern.) Wilbur | map | |
| Sabatia gentianoides Ell. | map | |
| Sabatia kennedyana Fern. | map | |
| Sabatia quadrangula Wilbur | map | images (1) (2) (3) |
| Sabatia stellaris Pursh | map | |
| Saccharum alopecuroides (L.) Nutt. | map | images (1) (2) (3) |
| Saccharum baldwinii Spreng. | map | |
| Saccharum brevibarbe (Michx.) Pers. | map | images (1) (2) |
| Saccharum coarctatum (Michx.) Pers. | map | |
| Saccharum contortum (Ell.) Nutt. | map | images (1) (2) (3) |
| Saccharum giganteum (Walt.) Pers. | map | images (1) (2) (3) |
| Sacciolepis indica (L.) Chase | map | |
| Sacciolepis striata (L.) Nash | map | images (1) (2) |
| Sageretia minutiflora (Michx.) C. Mohr | map | |
| Sagina decumbens (Ell.) Torr. & Gray | map | |
| Sagittaria australis (J.G. Sm.) Small | map | |
| Sagittaria calycina Engelm. | map | |
| Sagittaria engelmanniana J.G. Sm. | map | |
| Sagittaria fasciculata E.O. Beal | map | |
| Sagittaria graminea Michx. var. chapmanii J.G. Sm. | map | |
| Sagittaria graminea Michx. var. graminea | map | |
| Sagittaria graminea Michx. var. platyphylla (Engelm.) J.G. Sm. | map | |
| Sagittaria graminea Michx. var. weatherbiana (Fern.) Bogin | map | |
| Sagittaria isoetiformis J.G. Sm. | map | |
| Sagittaria lancifolia L. var. lancifolia | map | images (1) (2) (3) |
| Sagittaria lancifolia L. var. media Micheli | map | |
| Sagittaria latifolia Willd. var. latifolia | map | |
| Sagittaria latifolia Willd. var. obtusa (Engelm.) Wieg. | map | images (1) (2) |
| Sagittaria latifolia Willd. var. pubescens (Muhl. ex Nutt.) J.G. Sm. | map | |
| Sagittaria montevidensis Cham. & Schlecht | map | |
| Sagittaria subulata (L.) Buch. | map | images (1) (2) |
| Salicornia bigelovii Torr. | map | |
| Salicornia virginica L. | map | |
| Salix babylonica L. | map | |
| Salix caroliniana Michx. | map | |
| Salix caroliniana x nigra | map | |
| Salix cinerea L. | map | |
| Salix humilis Marsh. var. humilis | map | |
| Salix humilis Marsh. var. tristis (Ait.) Griggs | map | |
| Salix nigra Marsh. | map | images (1) (2) (3) |
| Salix sericea Marsh. | map | |
| Salpichroa origanifolia (Lam.) Baill. | map | images (1) (2) (3) (4) |
| Salsola kali L. | map | images (1) (2) (3) |
| Salvia azurea Michx. ex Lam. | map | images (1) (2) |
| Salvia coccinea P.J. Buchoz ex Etlinger | map | |
| Salvia lyrata L. | map | images (1) (2) (3) |
| Salvia urticifolia L. | map | |
| Salvinia minima Baker | map | |
| Sambucus canadensis L. | map | images (1) (2) (3) |
| Samolus valerandi L. ssp. parviflorus (Raf.) Hulten | map | images (1) (2) |
| Sanguinaria canadensis L. | map | images (1) |
| Sanguisorba annua (Nutt. ex Hook.) Torr. & Gray | map | |
| Sanguisorba canadensis L. | map | |
| Sanicula canadensis L. | map | |
| Sanicula marilandica L. | map | |
| Sanicula odorata (Raf.) K.M. Pryer & L.R. Phillippe | map | |
| Sanicula smallii Bickn. | map | |
| Sanicula trifoliata Bickn. | map | |
| Santolina chamaecyparissus L. | map | |
| Sapium sebiferum (L.) Roxb. | map | |
| Saponaria officinalis L. | map | |
| Sarcocornia perennis (P. Mill.) A.J. Schott | map | images (1) (2) (3) (4) |
| Sarracenia flava L. | map | images (1) (2) (3) (4) |
| Sarracenia minor Walt. | map | images (1) (2) |
| Sarracenia psittacina Michx. | map | |
| Sarracenia purpurea L. | map | images (1) (2) (3) |
| Sarracenia rubra Walt. ssp. jonesii (Wherry) Wherry | map | images (1) (2) |
| Sarracenia rubra Walt. ssp. rubra | map | images (1) |
| Sarracenia x catesbaei Elliott | map | images (1) (2) (3) |
| Sarracenia x rehderi Bell | map | |
| Sassafras albidum (Nutt.) Nees | map | images (1) (2) |
| Saururus cernuus L. | map | images (1) (2) |
| Saxifraga careyana Gray | map | |
| Saxifraga michauxii Britt. | map | |
| Saxifraga micranthidifolia (Haw.) Steud. | map | |
| Saxifraga virginiensis Michx. | map | |
| Scandix pecten-veneris L. | map | images (1) |
| Schisandra glabra (Bickn.) Rehd. | map | |
| Schizachyrium scoparium (Michx.) Nash | map | images (1) (2) |
| Schoenolirion croceum (Michx.) Wood | map | |
| Schwalbea americana L. | map | |
| Scirpus americanus Pers. | map | images (1) (2) (3) |
| Scirpus atrovirens Willd. | map | |
| Scirpus californicus (C.A. May.) Steud. | map | |
| Scirpus cyperinus (L.) Kunth | map | images (1) (2) (3) |
| Scirpus divaricatus Ell. | map | |
| Scirpus erectus Poir. | map | |
| Scirpus etuberculatus (Steud.) Kuntze | map | |
| Scirpus etuberculatus x S. subterminalis | map | |
| Scirpus expansus Fern. | map | |
| Scirpus georgianus Harper | map | |
| Scirpus hallii Gray | map | |
| Scirpus koilolepis (Steud.) Gleason | map | |
| Scirpus lineatus Michx. | map | |
| Scirpus pendulus Muhl. | map | |
| Scirpus polyphyllus Vahl | map | |
| Scirpus pungens Vahl | map | |
| Scirpus purshianus Fern. | map | |
| Scirpus robustus Pursh | map | images (1) |
| Scirpus subterminalis Torr. | map | |
| Scirpus tabernaemontani K.C. Gmel. | map | |
| Scleranthus annuus L. | map | images (1) (2) (3) |
| Scleria baldwinii (Torr.) Steud. | map | |
| Scleria ciliata Michx. var. ciliata | map | images (1) |
| Scleria ciliata Michx. var. glabra (Chapman) Fairey | map | |
| Scleria georgiana Core | map | |
| Scleria minor W. Stone | map | |
| Scleria oligantha Michx. | map | |
| Scleria pauciflora Muhl. ex Willd. | map | |
| Scleria reticularis Michx. | map | |
| Scleria triglomerata Michx. | map | |
| Scleria verticillata Muhl ex Willd. | map | images (1) (2) (3) (4) |
| Sclerolepis uniflora (Walt.) B.S.P. | map | |
| Scoparia dulcis L. | map | images (1) (2) (3) |
| Scrophularia marilandica L. | map | |
| Scutellaria elliptica Muhl. ex Spreng. | map | images (1) |
| Scutellaria incana Biehler var. punctata (Chapman) C. Mohr | map | |
| Scutellaria integrifolia L. | map | images (1) (2) |
| Scutellaria lateriflora L. | map | images (1) (2) |
| Scutellaria mellichampii Small | map | |
| Scutellaria nervosa Pursh | map | |
| Scutellaria ocmulgee Small | map | |
| Scutellaria ovata Hill | map | |
| Scutellaria parvula Michx. | map | |
| Scutellaria racemosa Pers. | map | images (1) (2) (3) |
| Scutellaria serrata Andr. | map | |
| Sebastiania fruticosa (Bartr.) Fern. | map | |
| Secale cereale L. | map | |
| Sedum pusillum Michx. | map | images (1) (2) (3) |
| Sedum sarmentosum Bunge | map | |
| Sedum telephioides Michx. | map | |
| Sedum ternatum Michx. | map | |
| Selaginella acanthonota Underwoood | map | images (1) (2) |
| Selaginella apoda (L.) Spring | map | |
| Selaginella rupestris (L.) Spring | map | |
| Selaginella tortipila A. Braun | map | images (1) (2) |
| Senecio anonymus Wood | map | images (1) (2) |
| Senecio aureus L. | map | |
| Senecio glabellus Poir. | map | images (1) (2) (3) |
| Senecio millefolium Torr. & Gray | map | images (1) (2) (3) (4) (5) |
| Senecio obovatus Muhl. ex Willd. | map | |
| Senecio tomentosus Michx. | map | images (1) (2) |
| Senecio vulgaris L. | map | images (1) |
| Senna hebecarpa (Fern.) Irwin & Barneby | map | |
| Senna marilandica (L.) Link | map | |
| Senna obtusifolia (L.) Irwin & Barneby | map | images (1) |
| Senna occidentalis (L.) Link | map | images (1) (2) (3) |
| Serenoa repens (Bartr.) Small | map | images (1) (2) |
| Sesbania drummondii (Rydb.) Cory | map | |
| Sesbania exaltata (Raf.) Rydb. ex A.W. Hill | map | images (1) (2) (3) (4) |
| Sesbania punicea (Cav.) Benth. | map | images (1) (2) (3) |
| Sesuvium maritimum (Walt.) B.S.P. | map | |
| Sesuvium portulacastrum (L.) L. | map | images (1) (2) (3) |
| Setaria corrugata (Ell.) J.A. Schultes | map | |
| Setaria faberi Herrm. | map | |
| Setaria glauca (L.) Beauv. | map | |
| Setaria italica (L.) Beauv. | map | |
| Setaria macrosperma (Scribn. & Merr.) K. Schum. | map | |
| Setaria magna Griseb. | map | images (1) (2) |
| Setaria parviflora (Poir.) Kerguelen | map | images (1) (2) (3) |
| Setaria viridis (L.) Beauv. | map | |
| Seymeria cassioides (J.F. Gmel.) Blake | map | images (1) (2) (3) (4) |
| Seymeria pectinata Pursh | map | images (1) (2) (3) |
| Sherardia arvensis L. | map | images (1) |
| Shortia galacifolia Torr. & Gray | map | |
| Sibara virginica (L.) Rollins | map | |
| Sicyos angulatus L. | map | images (1) (2) (3) (4) |
| Sida acuta Burm. f. | map | |
| Sida elliottii Torr. & Gray | map | |
| Sida rhombifolia L. | map | images (1) (2) |
| Sida spinosa L. | map | |
| Sideroxylon lanuginosum Michx. | map | |
| Sideroxylon lycioides L. | map | |
| Sideroxylon tenax L. | map | images (1) (2) |
| Silene antirrhina L. | map | |
| Silene armeria L. | map | |
| Silene caroliniana Walt. | map | |
| Silene gallica L. | map | |
| Silene latifolia Poir. ssp. alba (P. Mill.) Greuter & Burdet | map | |
| Silene ovata Pursh | map | |
| Silene stellata (L.) Ait. f. | map | |
| Silene virginica L. | map | |
| Silene vulgaris (Moench) Garcke | map | |
| Silphium asteriscus L. | map | images (1) |
| Silphium compositum Michx. | map | |
| Silphium terebinthinaceum Jacq. | map | |
| Sinapis arvensis L. | map | |
| Sisymbrium officinale (L.) Scop. | map | images (1) (2) (3) |
| Sisyrinchium albidum Raf. | map | |
| Sisyrinchium angustifolium P. Mill. | map | images (1) (2) |
| Sisyrinchium atlanticum Bickn. | map | |
| Sisyrinchium dichotomum Bickn. | map | |
| Sisyrinchium fuscatum Bickn. | map | |
| Sisyrinchium miamiense Bickn. | map | |
| Sisyrinchium mucronatum Michx. | map | images (1) (2) |
| Sisyrinchium nashii Bickn. | map | |
| Sisyrinchium rosulatum Bickn. | map | images (1) (2) (3) |
| Sium suave Walt. | map | |
| Smallanthus uvedalius (L.) Mackenzie ex Small | map | images (1) (2) |
| Smilax auriculata Walt. | map | |
| Smilax biltmoreana (Small) J.B.S. Norton ex Pennell | map | |
| Smilax bona-nox L. | map | |
| Smilax glauca Walt. | map | images (1) (2) |
| Smilax herbacea L. | map | |
| Smilax hugeri (Small) J.B.S. Norton ex Pennell | map | |
| Smilax laurifolia L. | map | images (1) |
| Smilax pseudochina L. | map | |
| Smilax pulverulenta Michx. | map | |
| Smilax pumila Walt. | map | |
| Smilax rotundifolia L. | map | |
| Smilax smallii Morong | map | |
| Smilax tamnoides L. | map | |
| Smilax walteri Pursh | map | images (1) (2) |
| Solanum americanum P. Mill. | map | images (1) (2) |
| Solanum capsicastrum Link ex Schauer | map | |
| Solanum capsicoides All. | map | |
| Solanum carolinense L. | map | images (1) (2) (3) |
| Solanum dimidiatum Raf. | map | |
| Solanum elaeagnifolium Cav. | map | |
| Solanum nigrum L. | map | |
| Solanum pseudocapsicum L. | map | |
| Solanum pseudogracile Heiser | map | |
| Solanum rostratum Dunal | map | |
| Solanum sisymbriifolium Lam. | map | images (1) |
| Solidago arguta Ait. var. arguta | map | |
| Solidago arguta Ait. var. boottii (Hook.) Palmer & Steyermark | map | |
| Solidago arguta Ait. var. caroliniana Gray | map | |
| Solidago auriculata Shuttlew. ex Blake | map | |
| Solidago bicolor L. | map | |
| Solidago caesia L. | map | images (1) (2) |
| Solidago canadensis L. var. scabra Torr. & Gray | map | |
| Solidago curtisii Torr. & Gray | map | |
| Solidago erecta Pursh | map | |
| Solidago fistulosa P. Mill. | map | |
| Solidago flexicaulis L. | map | |
| Solidago gigantea Ait. | map | |
| Solidago gracillima Torr. & Gray | map | |
| Solidago juncea Ait. | map | |
| Solidago latissimifolia P. Mill. | map | |
| Solidago leavenworthii Torr. & Gray | map | |
| Solidago nemoralis Ait. | map | |
| Solidago odora Ait. | map | images (1) (2) |
| Solidago patula Muhl. ex Willd. var. patula | map | |
| Solidago patula Muhl. ex Willd. var. strictula Torr. & Gray | map | |
| Solidago petiolaris Ait. | map | |
| Solidago pinetorum Small | map | |
| Solidago ptarmicoides (Nees) Boivin | map | |
| Solidago puberula Nutt. var. puberula | map | |
| Solidago puberula Nutt. var. pulverulenta (Nutt.) Chapman | map | |
| Solidago radula Nutt. | map | |
| Solidago rigida L. | map | |
| Solidago roanensis Porter | map | |
| Solidago rugosa P. Mill. var. celtidifolia (Small) Fern. | map | |
| Solidago rugosa P. Mill. var. rugosa | map | |
| Solidago sempervirens L. | map | images (1) (2) (3) (4) |
| Solidago speciosa Nutt. | map | |
| Solidago sphacelata Raf. | map | |
| Solidago stricta Ait. | map | images (1) (2) (3) (4) |
| Solidago tortifolia Ell. | map | |
| Solidago ulmifolia Muhl. ex Willd. | map | |
| Solidago verna M.A. Curtis | map | |
| Soliva sessilis Ruiz & Pavon | map | images (1) (2) (3) |
| Sonchus asper (L.) Hill | map | images (1) (2) |
| Sonchus oleraceus L. | map | images (1) (2) (3) (4) |
| Sorbus americana Marsh. | map | images (1) |
| Sorghastrum elliottii (C. Mohr) Nash | map | |
| Sorghastrum nutans (L.) Nash | map | images (1) (2) (3) |
| Sorghastrum secundum (Ell.) Nash | map | images (1) (2) |
| Sorghum halepense (L.) Pers. | map | images (1) (2) (3) (4) |
| Sparganium americanum Nutt. | map | |
| Spartina alterniflora Loisel | map | images (1) (2) |
| Spartina bakeri Merr. | map | |
| Spartina cynosuroides (L.)Roth | map | |
| Spartina patens (Ait.) Muhl. | map | images (1) (2) |
| Spergula arvensis L. | map | |
| Spergularia salina J. & K. Presl | map | |
| Spermacoce glabra Michx. | map | |
| Spermolepis divaricata (Walt.) Raf. ex Ser. | map | |
| Spermolepis echinata (Nutt. ex DC.) Heller | map | images (1) |
| Sphenoclea zeylanica Gaertn. | map | |
| Sphenopholis filiformis (Chapman) Scribn. | map | |
| Sphenopholis intermedia (Rydb.) Rydb. | map | |
| Sphenopholis nitida (Biehler) Scribn. | map | |
| Sphenopholis obtusata (Michx.) Scribn. | map | |
| Sphenopholis pensylvanica (L.) A.S. Hitchc. | map | |
| Sphenopholis x pallens (Biehler) Scribn. | map | |
| Spigelia marilandica (L.) L. | map | images (1) |
| Spiraea japonica L. f. | map | |
| Spiraea tomentosa L. | map | |
| Spiranthes brevilabris Lindl. var. floridana (Wherry) Luer | map | |
| Spiranthes cernua (L.) L.C. Rich | map | |
| Spiranthes lacera (Raf.) Raf. var. gracilis (Bigelow) Luer | map | |
| Spiranthes laciniata (Small) Ames | map | |
| Spiranthes longilabris Lindl. | map | |
| Spiranthes odorata (Nutt.) Lindl. | map | |
| Spiranthes ovalis Lindl. var. erostellata Catling | map | |
| Spiranthes praecox (Walt.) S. Wats. | map | |
| Spiranthes tuberosa Raf. | map | |
| Spiranthes vernalis Engelm. & Gray | map | |
| Spirodela polyrrhiza (L.) Schleid. | map | |
| Spirodela punctata (G.F.W. Mey.) C.H. Thompson | map | |
| Sporobolus clandestinus (Biehler) A.S. Hitchc. | map | |
| Sporobolus curtisii (Vasey ex Beal) Small ex Scribn. | map | |
| Sporobolus floridanus Chapman | map | |
| Sporobolus indicus (L.) R. Br. | map | images (1) |
| Sporobolus junceus (Beauv.) Kunth | map | images (1) |
| Sporobolus pinetorum Weakley & P.M. Peterson | map | |
| Sporobolus teretifolius Harper | map | |
| Sporobolus vaginiflorus (Torr. ex Gray) Wood | map | |
| Sporobolus virginicus (L.) Kunth | map | images (1) (2) |
| Stachys clingmanii Small | map | |
| Stachys eplingii J. Nelson | map | |
| Stachys floridana Shuttlew. ex Benth. | map | images (1) (2) (3) |
| Stachys aspera Michx. | map | |
| Stachys hyssopifolia Michx. | map | |
| Stachys latidens Small ex Britt. | map | |
| Stachys nuttallii Shuttlew. ex Benth. | map | |
| Stachys tenuifolia Willd. | map | |
| Staphylea trifolia L. | map | |
| Steinchisma hians (Ell.) Nash | map | |
| Stellaria graminea L. | map | images (1) (2) |
| Stellaria media (L.) Vill. | map | images (1) (2) |
| Stellaria pubera Michx. | map | |
| Stenanthium gramineum (Ker-Gawl.) Morong | map | |
| Stenotaphrum secundatum (Walt.) Kuntze | map | |
| Stewartia malacodendron L. | map | |
| Stewartia ovata (Cav.) Weatherby | map | |
| Stillingia aquatica Chapman | map | |
| Stillingia sylvatica Garden ex L. | map | images (1) (2) |
| Stipulicida setacea Michx. | map | images (1) (2) (3) (4) |
| Stokesia laevis (Hill) Greene | map | images (1) |
| Striga asiatica (L.) Kuntze | map | |
| Strophostyles helvula (L.) Ell. | map | |
| Strophostyles umbellata (Muhl. ex Willd.) Britt. | map | images (1) |
| Stylisma aquatica (Walt.) Raf. | map | |
| Stylisma humistrata (Walt.) Chapman | map | |
| Stylisma patens (Desr.) Myint ssp. angustifolia (Nash) Myint | map | |
| Stylisma patens (Desr.) Myint ssp. patens | map | images (1) (2) |
| Stylisma pickeringii (Torr. ex M.A. Curtis) Gray | map | images (1) |
| Stylodon carneus (Medik.) Moldenke | map | |
| Stylosanthes biflora (L.) B.S.P. | map | images (1) (2) |
| Styrax americanus Lam. var. americanus | map | images (1) (2) (3) |
| Styrax americanus Lam. var. pulverulentus (Michx.) Perkins ex Rehd. | map | |
| Styrax grandifolius Ait. | map | |
| Suaeda linearis (Ell.) Moq. | map | |
| Symphoricarpos orbiculatus Moench | map | images (1) (2) |
| Symphyotrichum novi-belgii (L.) Nesom var. elodes (Torr. & Gray) Nesom | map | |
| Symplocos tinctoria (L.) L'Her. | map | images (1) |
| Syngonanthus flavidulus (Michx.) Ruhl. | map | |