| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| SEDIP | Senecio dimorphophyllus Greene var. paysonii T.M. Barkl. | Packera dimorphophylla var. paysonii | Asteraceae
|
| SEDI4 | Senecio dimorphophyllus Greene | Packera dimorphophylla ssp. dimorphophylla | Asteraceae
|
| SEDI9 | Senecio discoideus (Hook.) Britt. | Packera pauciflora | Asteraceae
|
| SEDOL2 | Senecio douglasii DC. ssp. longilobus (Benth.) W.A. Weber | Senecio flaccidus var. flaccidus | Asteraceae
|
| SEDOJ | Senecio douglasii DC. var. jamesii (Torr. & Gray) Ediger ex Correll & Johnston | Senecio flaccidus var. flaccidus | Asteraceae
|
| SEDOL | Senecio douglasii DC. var. longilobus (Benth.) L. Benson | Senecio flaccidus var. flaccidus | Asteraceae
|
| SEDOM | Senecio douglasii DC. var. monoensis (Greene) Jepson | Senecio flaccidus var. monoensis | Asteraceae
|
| SEDOT | Senecio douglasii DC. var. tularensis Munz | Senecio flaccidus var. douglasii | Asteraceae
|
| SEDO2 | Senecio douglasii DC. | Senecio flaccidus var. douglasii | Asteraceae
|
| SEEL | Senecio elegans L. | redpurple ragwort | Asteraceae
|
| SEEL2 | Senecio elmeri Piper | Elmer's ragwort | Asteraceae
|
| SEERK2 | Senecio eremophilus Richards. ssp. kingii (Rydb.) G.W. Douglas & G. Ruyle-Douglas | Senecio eremophilus var. kingii | Asteraceae
|
| SEERM2 | Senecio eremophilus Richards. ssp. macdougalii (Heller) G.W. Douglas & G. Ruyle-Douglas | Senecio eremophilus var. macdougalii | Asteraceae
|
| SEERE | Senecio eremophilus Richards. var. eremophilus | desert ragwort | Asteraceae
|
| SEERK | Senecio eremophilus Richards. var. kingii (Rydb.) Greenm. | King's ragwort | Asteraceae
|
| SEERM | Senecio eremophilus Richards. var. macdougalii (Heller) Cronq. | MacDougal's ragwort | Asteraceae
|
| SEER2 | Senecio eremophilus Richards. | desert ragwort | Asteraceae
|
| SEER4 | Senecio ertterae T.M. Barkl. | Ertter's ragwort | Asteraceae
|
| SEER5 | Senecio erucifolius L. | hoary ragwort | Asteraceae
|
| SEEUL | Senecio eurycephalus Torr. & Gray ex Gray var. lewisrosei (J.T. Howell) T.M. Barkl. | Packera eurycephala var. lewisrosei | Asteraceae
|
| SEEU | Senecio eurycephalus Torr. & Gray ex Gray | Packera eurycephala var. eurycephala | Asteraceae
|
| SEEU2 | Senecio eurypterus Greenm. | Packera neomexicana var. neomexicana | Asteraceae
|
| SEEX2 | Senecio exaltatus Nutt. | Senecio integerrimus var. exaltatus | Asteraceae
|
| SEFE2 | Senecio fedifolius Rydb. | Packera debilis | Asteraceae
|
| SEFEL | Senecio fendleri Gray var. lanatus Osterhout | Packera fendleri | Asteraceae
|
| SEFE | Senecio fendleri Gray | Packera fendleri | Asteraceae
|
| SEFI2 | Senecio filifolius Nutt., non Berg. | Senecio flaccidus var. flaccidus | Asteraceae
|
| SEFLD | Senecio flaccidus Less. var. douglasii (DC.) B.L. Turner & T.M. Barkl. | Douglas' ragwort | Asteraceae
|
| SEFLF | Senecio flaccidus Less. var. flaccidus | threadleaf ragwort | Asteraceae
|
| SEFLM | Senecio flaccidus Less. var. monoensis (Greene) B.L. Turner & T.M. Barkl. | Mono ragwort | Asteraceae
|
| SEFL3 | Senecio flaccidus Less. | threadleaf ragwort | Asteraceae
|
| SEFL6 | Senecio flavulus Greene | Packera pseudaurea var. flavula | Asteraceae
|
| SEFL | Senecio flettii Wieg. | Packera flettii | Asteraceae
|
| SEFL5 | Senecio flocciferus DC. | Malacothrix floccifera | Asteraceae
|
| SEFOH | Senecio foetidus J.T. Howell var. hydrophiloides (Rydb.) T.M. Barkl. ex Cronq. | Senecio hydrophiloides | Asteraceae
|
| SEFO | Senecio foetidus J.T. Howell | Senecio hydrophiloides | Asteraceae
|
| SEFR2 | Senecio franciscanus Greene | Packera franciscana | Asteraceae
|
| SEFRB2 | Senecio fremontii Torr. & Gray ssp. blitoides (Greene) W.A. Weber | Senecio fremontii var. blitoides | Asteraceae
|
| SEFRO2 | Senecio fremontii Torr. & Gray ssp. occidentalis (Gray) G.W. Douglas & G. Ruyle-Douglas | Senecio fremontii var. occidentalis | Asteraceae
|
| SEFRB | Senecio fremontii Torr. & Gray var. blitoides (Greene) Cronq. | dwarf mountain ragwort | Asteraceae
|
| SEFRF | Senecio fremontii Torr. & Gray var. fremontii | dwarf mountain ragwort | Asteraceae
|
| SEFRI | Senecio fremontii Torr. & Gray var. inexpectatus Cronq. | dwarf mountain ragwort | Asteraceae
|
| SEFRO | Senecio fremontii Torr. & Gray var. occidentalis Gray | dwarf mountain ragwort | Asteraceae
|
| SEFR3 | Senecio fremontii Torr. & Gray | dwarf mountain ragwort | Asteraceae
|
| SEFU2 | Senecio fulgens Rydb. | Packera streptanthifolia | Asteraceae
|
| SEFU | Senecio fuscatus auct. non Hayek | Tephroseris lindstroemii | Asteraceae
|
| SEGA | Senecio ganderi T.M. Barkl. & Beauchamp | Packera ganderi | Asteraceae
|
| SEGAF | Senecio gaspensis Greenm. var. firmifolius (Greenm.) Fern. | Packera paupercula | Asteraceae
|
| SEGA3 | Senecio gaspensis Greenm. | Packera paupercula | Asteraceae
|
| SEGI4 | Senecio gibbsonsii Greene | Senecio triangularis | Asteraceae
|
| SEGL | Senecio glabellus Poir. | Packera glabella | Asteraceae
|
| SEGL5 | Senecio glaucifolius Rydb. | Senecio eremophilus var. eremophilus | Asteraceae
|
| SEGL4 | Senecio glomeratus Desf. ex Poir. | Erechtites glomerata | Asteraceae
|
| SEGR8 | Senecio gracilis Pursh | Packera aurea | Asteraceae
|
| SEGR3 | Senecio greenei Gray | Packera greenei | Asteraceae
|
| SEGR9 | Senecio greggii Rydb. | Packera tampicana | Asteraceae
|
| SEHAD | Senecio hallii Britt. var. discoidea W.A. Weber | Packera cana | Asteraceae
|
| SEHA7 | Senecio hallii Britt. | Packera cana | Asteraceae
|
| SEHA9 | Senecio harbourii Rydb. | Packera cana | Asteraceae
|
| SEHA10 | Senecio harfordii Greenm. | Packera bolanderi var. harfordii | Asteraceae
|
| SEHA5 | Senecio hartianus Heller | Packera hartiana | Asteraceae
|
| SEHA6 | Senecio hartwegii Benth. | Roldana hartwegii | Asteraceae
|
| SEHE2 | Senecio hesperius Greene | Packera hesperia | Asteraceae
|
| SEHE4 | Senecio heterodoxus Greene ex Rydb. | Packera dimorphophylla ssp. dimorphophylla | Asteraceae
|
| SEHI3 | Senecio hieraciifolius L. | Erechtites hieraciifolia var. hieraciifolia | Asteraceae
|
| SEHO | Senecio holmii Greene | Senecio amplectens var. holmii | Asteraceae
|
| SEHO3 | Senecio hookeri Torr. & Gray | Senecio integerrimus var. exaltatus | Asteraceae
|
| SEHO2 | Senecio howellii Greene | Packera cana | Asteraceae
|
| SEHU | Senecio huachucanus Gray | Senecio multidentatus var. huachucanus | Asteraceae
|
| SEHY5 | Senecio hybridus (Willd.) Regel | Pericallis cuneata | Asteraceae
|
| SEHY | Senecio hydrophiloides Rydb. | tall groundwel | Asteraceae
|
| SEHY2 | Senecio hydrophilus Nutt. | water ragwort | Asteraceae
|
| SEHY3 | Senecio hyperborealis Greenm. | Packera hyperborealis | Asteraceae
|
| SEIM | Senecio imparipinnatus Klatt | Packera tampicana | Asteraceae
|
| SEIN | Senecio indecorus Greene | Packera indecora | Asteraceae
|
| SEINE | Senecio integerrimus Nutt. var. exaltatus (Nutt.) Cronq. | Columbia ragwort | Asteraceae
|
| SEINI | Senecio integerrimus Nutt. var. integerrimus | lambstongue ragwort | Asteraceae
|
| SEINL2 | Senecio integerrimus Nutt. var. lugens (Richards.) Boivin | Senecio lugens | Asteraceae
|
| SEINM | Senecio integerrimus Nutt. var. major (Gray) Cronq. | lambstongue ragwort | Asteraceae
|
| SEINO | Senecio integerrimus Nutt. var. ochroleucus (Gray) Cronq. | paleyellow ragwort | Asteraceae
|
| SEINS | Senecio integerrimus Nutt. var. scribneri (Rydb.) T.M. Barkl. | Scribner's ragwort | Asteraceae
|
| SEINV2 | Senecio integerrimus Nutt. var. vaseyi (Greenm.) Cronq. | Senecio integerrimus var. exaltatus | Asteraceae
|
| SEIN2 | Senecio integerrimus Nutt. | lambstongue ragwort | Asteraceae
|
| SEIOS | Senecio ionophyllus Greene var. sparsilobatus (Parish) Hall | Packera bernardina | Asteraceae
|
| SEIO | Senecio ionophyllus Greene | Packera ionophylla | Asteraceae
|
| SEJA | Senecio jacobaea L. | stinking willie | Asteraceae
|
| SEJO2 | Senecio jonesii Rydb. | Packera streptanthifolia | Asteraceae
|
| SEKI | Senecio kingii Rydb. | Senecio eremophilus var. kingii | Asteraceae
|
| SEKJ | Senecio kjellmanii Porsild | Tephroseris kjellmanii | Asteraceae
|
| SELA7 | Senecio laetiflorus Greene | Packera streptanthifolia | Asteraceae
|
| SELA4 | Senecio layneae Greene | Packera layneae | Asteraceae
|
| SELE8 | Senecio lemmonii Gray | Lemmon's ragwort | Asteraceae
|
| SELE10 | Senecio leonardii Rydb. | Packera streptanthifolia | Asteraceae
|
| SELE11 | Senecio lewisrosei J.T. Howell | Packera eurycephala var. lewisrosei | Asteraceae
|
| SELI8 | Senecio ligulifolius Greene | Packera macounii | Asteraceae
|
| SELI6 | Senecio lindstroemii (Ostenf.) Porsild | Tephroseris lindstroemii | Asteraceae
|
| SELO5 | Senecio lobatus Pers. | Packera glabella | Asteraceae
|
| SELO | Senecio longilobus Benth. | Senecio flaccidus var. flaccidus | Asteraceae
|
| SELO3 | Senecio longipetiolatus Rydb. | Packera streptanthifolia | Asteraceae
|
| SELUE2 | Senecio lugens Richards. var. exaltatus (Nutt.) Gray | Senecio integerrimus var. exaltatus | Asteraceae
|
| SELUO | Senecio lugens Richards. var. ochroleucus Gray | Senecio integerrimus var. ochroleucus | Asteraceae
|