The Plant List — A working list for all plant species

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You should refer instead to the current version of The Plant List.

Results

No plant names match your search for Penstemon erosus; we will try Penstemon instead.

766 plant name records match your search criteria Penstemon. The results are below.

• Genus Penstemon is in the family Plantaginaceae. Species epithets begin with: A B C D E F G H I J K L M N O P R S T U V W X Y

The results can also be downloaded as a CSV file.

See "Status", "Confidence level", "Source" for definitions.

Name	Status	Confi­dence level	Source
Penstemon abietinus Pennell	Unresolved		WCSP (in review)
Penstemon aboriginum M.E.Jones	Unresolved		WCSP (in review)
Penstemon absarokensis Evert	Unresolved		WCSP (in review)
Penstemon acaulis L.O.Williams	Unresolved		WCSP (in review)
Penstemon acaulis var. yampaensis (Penland) Neese	Unresolved		TRO
Penstemon acuminatus Douglas	Unresolved		WCSP (in review)
Penstemon acuminatus var. congestus M.E. Jones	Synonym		TRO
Penstemon adamsianus Howell	Unresolved		WCSP (in review)
Penstemon aggregatus Pennell	Synonym		TRO
Penstemon alamosensis Pennell & Nisbet	Unresolved		WCSP (in review)
Penstemon albertinus Greene	Unresolved		WCSP (in review)
Penstemon albidus Nutt.	Synonym		TRO
Penstemon albifloris England	Unresolved		WCSP (in review)
Penstemon albifluvis England	Synonym		TRO
Penstemon albomarginatus M.E.Jones	Unresolved		WCSP (in review)
Penstemon albrightii A.Nelson	Unresolved		WCSP (in review)
Penstemon alluviorum Pennell	Synonym		TRO
Penstemon alpinus Torr.	Synonym		TRO
Penstemon alpinus subsp. brandegeei (Porter ex Rydb.) Penland	Unresolved		TRO
Penstemon alpinus subsp. magnus (Pennell) Penland	Unresolved		TRO
Penstemon alpinus f. riparius (A. Nelson) Pennell	Unresolved		TRO
Penstemon alsinoides Greene	Unresolved		WCSP (in review)
Penstemon amabilis G.N.Jones	Unresolved		WCSP (in review)
Penstemon ambiguus Torr.	Accepted		TRO
Penstemon ambiguus subsp. laevissimus D.D. Keck	Synonym		TRO
Penstemon ambiguus var. laevissimus (D.D. Keck) N.H. Holmgren	Accepted		TRO
Penstemon ambiguus var. thurberi (Torr.) A. Gray	Synonym		TRO
Penstemon ammophilus N.H.Holmgren & L.M.Schultz	Unresolved		WCSP (in review)
Penstemon amoenus Kunze	Unresolved		WCSP (in review)
Penstemon amphorellae Crosswh.	Accepted		TRO
Penstemon amplexicaulis Moench	Unresolved		WCSP (in review)
Penstemon amplexicaulis Buckley	Unresolved		WCSP (in review)
Penstemon amplus A.Nelson	Unresolved		WCSP (in review)
Penstemon angelicus (I.M.Johnst.) Moran	Unresolved		WCSP (in review)
Penstemon anguineus Eastw.	Unresolved		WCSP (in review)
Penstemon angustifolius Nutt. ex Pursh	Synonym		TRO
Penstemon angustifolius var. caudatus (A. Heller) Rydb.	Synonym		TRO
Penstemon angustifolius subsp. caudatus (A. Heller) D.D. Keck	Unresolved		TRO
Penstemon angustifolius var. venosus (D.D. Keck) N.H. Holmgren	Unresolved		TRO
Penstemon angustifolius subsp. venosus D.D. Keck	Synonym		TRO
Penstemon antirrhinoides Benth.	Synonym		TRO
Penstemon antirrhinoides subsp. microphyllus (A. Gray) D.D. Keck	Synonym		TRO
Penstemon antirrhinoides var. microphyllus (A. Gray) Munz & I.M. Johnst.	Synonym		TRO
Penstemon apateticus Straw	Accepted		TRO
Penstemon arenarius Greene	Synonym		TRO
Penstemon arenicola A.Nelson	Unresolved		WCSP (in review)
Penstemon argutus Paxton	Unresolved		WCSP (in review)
Penstemon aridus Rydb.	Unresolved		WCSP (in review)
Penstemon arizonicus A.Heller	Unresolved		WCSP (in review)
Penstemon arkansanus Pennell	Synonym		TRO
Penstemon assurgens D.D.Keck	Unresolved		WCSP (in review)
Penstemon atropurpureus (Sweet) G. Don	Accepted		TRO
Penstemon attenuatus Douglas ex Lindl.	Synonym		TRO
Penstemon attenuatus subsp. militaris (Greene) D.D. Keck	Synonym		TRO
Penstemon attenuatus var. militaris (Greene) Cronquist	Unresolved		TRO
Penstemon attenuatus subsp. palustris (Pennell) D.D. Keck	Synonym		TRO
Penstemon attenuatus var. palustris (Pennell) Cronquist	Unresolved		TRO
Penstemon attenuatus subsp. pseudoprocerus (Rydb.) D.D. Keck	Synonym		TRO
Penstemon attenuatus var. pseudoprocerus (Rydb.) Cronquist	Unresolved		TRO
Penstemon atwoodii S.L.Welsh	Unresolved		WCSP (in review)
Penstemon auriberbis Pennell	Unresolved		WCSP (in review)
Penstemon auricomus A.Nelson ex Rydb.	Unresolved		WCSP (in review)
Penstemon auricomus A.Nelson	Unresolved		WCSP (in review)
Penstemon austinii Eastw.	Synonym		TRO
Penstemon australis Small	Unresolved		WCSP (in review)
Penstemon australis subsp. laxiflorus (Pennell) R.W. Benn.	Unresolved		TRO
Penstemon azureus Benth.	Synonym		TRO
Penstemon azureus subsp. angustissimus (A. Gray) D.D. Keck	Unresolved		TRO
Penstemon azureus var. angustissimus A. Gray	Synonym		TRO
Penstemon azureus var. parvulus A. Gray	Synonym		TRO
Penstemon azureus subsp. parvulus (A. Gray) D.D. Keck	Unresolved		TRO
Penstemon baccharifolius Hook.	Accepted		TRO
Penstemon baccharifolius var. schaffneri Hemsl.	Unresolved		WCSP (in review)
Penstemon bachimbensis Straw	Unresolved		TRO
Penstemon bakeri Greene	Unresolved		WCSP (in review)
Penstemon barbatus (Cav.) Roth	Unresolved		TRO
Penstemon barbatus (Cav.) Nutt.	Accepted		TRO
Penstemon barbatus var. labrosus A. Gray	Synonym		TRO
Penstemon barbatus subsp. torreyi (Benth.) D.D. Keck	Accepted		TRO
Penstemon barbatus subsp. trichander (A. Gray) D.D. Keck	Accepted		TRO
Penstemon barbatus var. trichander A. Gray	Synonym		TRO
Penstemon barbatus var. wislizeni A. Gray	Synonym		TRO
Penstemon barnebyi N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon barrettae A.Gray	Unresolved		WCSP (in review)
Penstemon berryi Eastw.	Synonym		TRO
Penstemon bicolor (Brandegee) Clokey & D.D. Keck	Accepted		TRO
Penstemon bolanius Straw	Unresolved		WCSP (in review)
Penstemon brachyanthus Pennell	Synonym		TRO
Penstemon bracteatus D.D.Keck	Unresolved		WCSP (in review)
Penstemon bradburii Pursh	Unresolved		WCSP (in review)
Penstemon brandegeei Porter ex Rydb.	Synonym		TRO
Penstemon brevibarbatus Crosswhite	Unresolved		TRO
Penstemon breviculus (D.D. Keck) G.T. Nisbet & R.C. Jacks.	Accepted		TRO
Penstemon breviflorus Lindl.	Synonym		TRO
Penstemon breviflorus subsp. glabrisepalus D.D. Keck	Synonym		TRO
Penstemon brevifolius (A. Gray) A. Nelson	Synonym		TRO
Penstemon brevilabris A.Gray	Unresolved		WCSP (in review)
Penstemon brevis A.Nelson	Unresolved		WCSP (in review)
Penstemon brevisepalus Pennell	Accepted		WCSP (in review)
Penstemon bridgesii A.Gray	Unresolved		WCSP (in review)
Penstemon brittoniorum Pennell	Synonym		TRO
Penstemon brittonoruro Pennell ex Peattie	Unresolved		WCSP (in review)
Penstemon × bryantae D.D.Keck	Unresolved		WCSP (in review)
Penstemon buckleyi Pennell	Unresolved		WCSP (in review)
Penstemon cacuminis Pennell	Unresolved		WCSP (in review)
Penstemon caelestinus Pennell	Unresolved		WCSP (in review)
Penstemon caeruleum Nutt.	Synonym		TRO
Penstemon caesius A.Gray	Unresolved		WCSP (in review)
Penstemon caespitosus Nutt. ex A.Gray	Unresolved		WCSP (in review)
Penstemon caespitosus subsp. desertipicti (A. Nelson) D.D. Keck	Synonym		TRO
Penstemon caespitosus var. desertipicti (A. Nelson) N.H. Holmgren	Unresolved		TRO
Penstemon caespitosus subsp. perbrevis Pennell	Synonym		TRO
Penstemon caespitosus var. perbrevis (Pennell) N.H. Holmgren	Unresolved		TRO
Penstemon caespitosus var. suffruticosus A. Gray	Synonym		TRO
Penstemon caespitosus subsp. suffruticosus (A. Gray) D.D. Keck	Unresolved		TRO
Penstemon calcareus Brandegee	Unresolved		WCSP (in review)
Penstemon calcareus M.E.Jones	Unresolved		WCSP (in review)
Penstemon californicus (Munz & I.M. Johnst.) D.D. Keck	Accepted		TRO
Penstemon calycosus Small	Synonym		TRO
Penstemon campanulatus (Cav.) Willd.	Accepted		TRO
Penstemon canescens (Britton) Britton	Accepted		TRO
Penstemon canescens f. brittoniorum (Pennell) Fernald	Accepted		TRO
Penstemon canescens subsp. brittoniorum (Pennell) Pennell	Synonym		TRO
Penstemon canosobarbatus Kellogg	Unresolved		WCSP (in review)
Penstemon cardinalis Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon cardinalis subsp. regalis (A. Nelson) G.T. Nisbet & R.C. Jacks.	Unresolved		TRO
Penstemon cardwellii Howell	Unresolved		WCSP (in review)
Penstemon carinatus Kellogg	Unresolved		WCSP (in review)
Penstemon carnosus Pennell	Unresolved		WCSP (in review)
Penstemon caryi Pennell	Unresolved		WCSP (in review)
Penstemon caudatus A. Heller	Synonym		TRO
Penstemon cedrosensis Krautter	Unresolved		WCSP (in review)
Penstemon centranthifolius (Benth.) Benth.	Accepted		TRO
Penstemon cephalanthus Pennell	Unresolved		WCSP (in review)
Penstemon cephalophorus Greene	Synonym		TRO
Penstemon cerrosensis Kellogg	Unresolved		WCSP (in review)
Penstemon chionophilus Greene	Unresolved		WCSP (in review)
Penstemon chionophilus Greene ex C.F.Baker	Unresolved		WCSP (in review)
Penstemon cinerascens Greene	Unresolved		WCSP (in review)
Penstemon cinerascens Greene ex C.F.Baker	Unresolved		WCSP (in review)
Penstemon cinereus Piper	Unresolved		WCSP (in review)
Penstemon cinicola D.D.Keck	Unresolved		WCSP (in review)
Penstemon cleburnei M.E. Jones	Synonym		TRO
Penstemon clevelandii A. Gray	Accepted		TRO
Penstemon clevelandii subsp. angelicus (I.M. Johnst.) Keck	Accepted		TRO
Penstemon clevelandii var. angelicus I.M. Johnst.	Synonym		TRO
Penstemon clevelandii subsp. connatus (Munz & I.M. Johnst.) D.D. Keck	Accepted		TRO
Penstemon clevelandii var. connatus Munz & I.M. Johnst.	Synonym		TRO
Penstemon clevelandii subsp. mohavensis D.D. Keck	Synonym		TRO
Penstemon clevelandii var. mohavensis (D.D. Keck) McMinn	Accepted		TRO
Penstemon clevelandii var. stephensii (Brandegee) Munz & I.M. Johnst.	Accepted		TRO
Penstemon clutei A.Nelson	Unresolved		WCSP (in review)
Penstemon cobaea Nutt.	Unresolved		WCSP (in review)
Penstemon cobaea var. purpureus Pennell	Synonym		TRO
Penstemon cobaea subsp. purpureus (Pennell) Pennell	Unresolved		TRO
Penstemon coccinatus Rydb.	Unresolved		WCSP (in review)
Penstemon coccineus Engelm.	Unresolved		WCSP (in review)
Penstemon coeruleus Torr.	Unresolved		WCSP (in review)
Penstemon coeruleus Nutt.	Unresolved		WCSP (in review)
Penstemon collinus A.Nelson	Unresolved		WCSP (in review)
Penstemon coloradoensis A. Nelson	Synonym		TRO
Penstemon coloradoensis subsp. sileri (A. Gray) Pennell	Synonym		TRO
Penstemon colvillii Huber	Unresolved		WCSP (in review)
Penstemon comarrhenus A.Gray	Unresolved		WCSP (in review)
Penstemon compactus (D.D. Keck) Crosswh.	Accepted		TRO
Penstemon concinnus D.D.Keck	Unresolved		WCSP (in review)
Penstemon confertus Douglas	Unresolved		WCSP (in review)
Penstemon confertus var. aberrans M.E. Jones	Synonym		TRO
Penstemon confertus var. attenuatus (Douglas ex Lindl.) M.E. Jones	Unresolved		TRO
Penstemon confertus var. geniculatus (Greene) Jeps.	Unresolved		TRO
Penstemon confertus var. globosus Piper	Synonym		TRO
Penstemon confertus var. modestus (Greene) Jeps.	Synonym		TRO
Penstemon confusus M.E.Jones	Unresolved		WCSP (in review)
Penstemon confusus subsp. patens (M.E. Jones) D.D. Keck	Synonym		TRO
Penstemon confusus var. patens M.E. Jones	Synonym		TRO
Penstemon congestus (M.E. Jones) Pennell	Synonym		TRO
Penstemon connatifolius A. Nelson	Synonym		TRO
Penstemon connatus Deppe	Unresolved		WCSP (in review)
Penstemon cordatus M.Martens & Galeotti	Unresolved		WCSP (in review)
Penstemon cordatus Walp.	Unresolved		WCSP (in review)
Penstemon cordifolius Benth.	Synonym		TRO
Penstemon corymbosus Benth.	Synonym		TRO
Penstemon crandallii A.Heller	Unresolved		WCSP (in review)
Penstemon crandallii A.Nelson	Unresolved		WCSP (in review)
Penstemon crandallii subsp. atratus D.D. Keck	Synonym		TRO
Penstemon crandallii var. atratus (D.D. Keck) N.H. Holmgren	Unresolved		TRO
Penstemon crandallii subsp. glabrescens (Pennell) D.D. Keck	Unresolved		TRO
Penstemon crandallii subsp. procumbens (Greene) D.D. Keck	Unresolved		TRO
Penstemon crandallii var. taosensis (D.D. Keck) G.T. Nisbet & R.C. Jacks.	Unresolved		TRO
Penstemon crassifolius Lindl.	Unresolved		WCSP (in review)
Penstemon crassifolius Shuttlew. ex Benth.	Unresolved		WCSP (in review)
Penstemon crassulus Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon crideri A.Nelson	Unresolved		WCSP (in review)
Penstemon cristatus Nutt.	Unresolved		WCSP (in review)
Penstemon cusickii A.Gray	Unresolved		WCSP (in review)
Penstemon cyananthus Hook.	Unresolved		WCSP (in review)
Penstemon cyananthus var. brandegeei Porter	Synonym		TRO
Penstemon cyananthus subsp. compactus D.D. Keck	Synonym		TRO
Penstemon cyananthus subsp. longiflorus Pennell	Synonym		TRO
Penstemon cyananthus subsp. subglaber (A. Gray) Pennell	Synonym		TRO
Penstemon cyananthus var. subglaber (A. Gray) N.H. Holmgren	Unresolved		TRO
Penstemon cyaneus Pennell	Unresolved		WCSP (in review)
Penstemon cyanocaulis Payson	Unresolved		WCSP (in review)
Penstemon cyathophorus Rydb.	Unresolved		WCSP (in review)
Penstemon dasyphyllus A. Gray	Accepted		TRO
Penstemon davidsonii Greene	Synonym		TRO
Penstemon davidsonii var. ellipticus (J.M. Coult. & Fisher) B. Boivin	Unresolved		TRO
Penstemon davidsonii subsp. menziesii D.D. Keck	Synonym		TRO
Penstemon davidsonii var. menziesii (D.D. Keck) Cronquist	Unresolved		TRO
Penstemon dayanus Howell	Synonym		TRO
Penstemon deamii Pennell	Synonym		TRO
Penstemon deaveri Crosswh.	Unresolved		WCSP (in review)
Penstemon debilis O'Kane & J.L.Anderson	Unresolved		WCSP (in review)
Penstemon decurvus Pennell ex Crosswh.	Unresolved		WCSP (in review)
Penstemon degeneri Crosswh.	Unresolved		WCSP (in review)
Penstemon depressus Greene	Unresolved		WCSP (in review)
Penstemon deserticola Piper	Unresolved		WCSP (in review)
Penstemon desertipicti A. Nelson	Synonym		TRO
Penstemon desertorum M.E.Jones	Unresolved		WCSP (in review)
Penstemon deustus Douglas	Unresolved		WCSP (in review)
Penstemon deustus var. arenarius (Greene) Jeps.	Unresolved		TRO
Penstemon deustus subsp. heterander (Torr. & A. Gray) Pennell & D.D. Keck	Synonym		TRO
Penstemon deustus var. heterander (Torr. & A. Gray) Cronquist	Unresolved		TRO
Penstemon deustus subsp. sudans (M.E. Jones) Pennell & D.D. Keck	Unresolved		TRO
Penstemon deustus subsp. variabilis (Suksd.) Pennell & D.D. Keck	Synonym		TRO
Penstemon deustus var. variabilis (Suksd.) Cronquist	Unresolved		TRO
Penstemon diffusus Douglas	Unresolved		WCSP (in review)
Penstemon digitalis Nutt. ex Sims	Synonym		TRO
Penstemon digitalis var. attenuatus (Douglas ex Lindl.) Trautv.	Synonym		TRO
Penstemon digitalis var. gracilis (Nutt.) Trautv.	Synonym		TRO
Penstemon dimorphus Kuntze	Unresolved		WCSP (in review)
Penstemon diphyllus Rydb.	Unresolved		WCSP (in review)
Penstemon discolor D.D.Keck	Unresolved		WCSP (in review)
Penstemon dissectus Elliott	Unresolved		WCSP (in review)
Penstemon distans N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon divergens M.E.Jones	Unresolved		WCSP (in review)
Penstemon dolius M.E.Jones	Unresolved		WCSP (in review)
Penstemon dolius var. duchesnensis N.H. Holmgren	Synonym		TRO
Penstemon douglasii Hook.	Unresolved		WCSP (in review)
Penstemon dubius Davidson	Unresolved		WCSP (in review)
Penstemon duchesnensis (N.H. Holmgren) Neese	Accepted		TRO
Penstemon eastwoodiae A.Heller	Unresolved		WCSP (in review)
Penstemon eatonii A.Gray	Unresolved		WCSP (in review)
Penstemon eatonii subsp. exsertus (A. Nelson) D.D. Keck	Unresolved		TRO
Penstemon eatonii subsp. undosus (M.E. Jones) D.D. Keck	Unresolved		TRO
Penstemon eatonii var. undosus M.E. Jones	Synonym		TRO
Penstemon × edithae English	Unresolved		WCSP (in review)
Penstemon elegans Poir.	Unresolved		WCSP (in review)
Penstemon elegantulus Pennell	Unresolved		WCSP (in review)
Penstemon ellipticus J.M. Coult. & Fisher	Synonym		TRO
Penstemon eriantherus Nutt. ex Pursh	Unresolved		WCSP (in review)
Penstemon eriantherus Nutt.	Unresolved		WCSP (in review)
Penstemon eriantherus var. cleburnei (M.E. Jones) Dorn	Unresolved		TRO
Penstemon eriantherus subsp. saliens (Rydb.) Pennell	Unresolved		TRO
Penstemon eriantherus var. whitedii (Piper) A. Nelson	Unresolved		TRO
Penstemon euglaucus English	Unresolved		WCSP (in review)
Penstemon exilifolius A. Nelson	Synonym		TRO
Penstemon eximius Keck	Accepted		TRO
Penstemon exsertus A. Nelson	Synonym		TRO
Penstemon fasciculatus A. Gray	Accepted		TRO
Penstemon fendleri Torr. & A. Gray	Accepted		TRO
Penstemon filifolius Nutt. ex Benth.	Unresolved		WCSP (in review)
Penstemon filiformis (D.D. Keck) D.D. Keck	Accepted		TRO
Penstemon filisepalis Straw	Accepted		TRO
Penstemon flavescens Pennell	Unresolved		WCSP (in review)
Penstemon flaviflorus M.E.Jones	Unresolved		WCSP (in review)
Penstemon floribundus Danley	Unresolved		WCSP (in review)
Penstemon floridus Brandegee	Unresolved		WCSP (in review)
Penstemon floridus subsp. austinii (Eastw.) D.D. Keck	Synonym		TRO
Penstemon floridus var. austinii (Eastw.) N.H. Holmgren	Unresolved		TRO
Penstemon flowersii Neese & S.L.Welsh	Unresolved		WCSP (in review)
Penstemon formosus A. Nelson	Synonym		TRO
Penstemon francisci-pennellii Crosswh.	Synonym		TRO
Penstemon franklinii S.L.Welsh	Unresolved		WCSP (in review)
Penstemon fremontii Torr. & A. Gray	Synonym		TRO
Penstemon fremontii var. subglaber A. Gray	Synonym		TRO
Penstemon frutescens Lamb.	Synonym		TRO
Penstemon fruticiformis Coville	Unresolved		WCSP (in review)
Penstemon fruticiformis subsp. amargosae D.D. Keck	Synonym		TRO
Penstemon fruticiformis var. amargosae (D.D. Keck) N.H. Holmgren	Unresolved		TRO
Penstemon fruticiformis var. incertus (Brandegee) Munz & I.M. Johnst.	Unresolved		TRO
Penstemon fruticosus (Pursh) Greene	Accepted		TRO
Penstemon fruticosus var. scouleri (Douglas ex Lindl.) Cronquist	Accepted		TRO
Penstemon fruticosus subsp. serratus D.D. Keck	Synonym		TRO
Penstemon fruticosus var. serratus (D.D. Keck) Cronquist	Accepted		TRO
Penstemon gairdneri Hook.	Unresolved		WCSP (in review)
Penstemon gairdneri subsp. hians (Piper) D.D. Keck	Unresolved		TRO
Penstemon gairdneri var. hians Piper	Synonym		TRO
Penstemon gairdneri subsp. oreganus (A. Gray) D.D. Keck	Unresolved		TRO
Penstemon gairdneri var. oreganus A. Gray	Synonym		TRO
Penstemon galloensis G.L. Nesom	Accepted		TRO
Penstemon garrettii Pennell	Synonym		TRO
Penstemon geniculatus Greene	Synonym		TRO
Penstemon gentianoides (Kunth) Poir.	Accepted		TRO
Penstemon gentryi Standl.	Accepted		TRO
Penstemon gibbensii Dorn	Unresolved		WCSP (in review)
Penstemon giganteus C.Morren	Unresolved		WCSP (in review)
Penstemon glaber Pursh	Accepted		TRO
Penstemon glaber var. alpinus (Torr.) A. Gray	Accepted		TRO
Penstemon glaber var. brandegeei (Porter) C.C. Freeman	Accepted		TRO
Penstemon glaber var. fremontii (Torr. & A. Gray) M.E. Jones	Accepted		TRO
Penstemon glaber var. utahensis S. Watson	Synonym		TRO
Penstemon glaber var. wardii (A. Gray) M.E. Jones	Accepted		TRO
Penstemon glaberrimus Bevis ex W.H.Baxter	Unresolved		WCSP (in review)
Penstemon glabrescens Pennell	Synonym		TRO
Penstemon glandulosus Douglas ex Lindl.	Unresolved		WCSP (in review)
Penstemon glandulosus subsp. chelanensis D.D. Keck	Synonym		TRO
Penstemon glandulosus var. chelanensis (D.D. Keck) Cronquist	Unresolved		TRO
Penstemon glastifolius Greene	Unresolved		WCSP (in review)
Penstemon glaucifolius A.Gray	Unresolved		WCSP (in review)
Penstemon glaucinus Pennell	Unresolved		WCSP (in review)
Penstemon glaucophyllus Scheele	Unresolved		WCSP (in review)
Penstemon glaucus Graham	Unresolved		WCSP (in review)
Penstemon glaucus var. stenosepalus A. Gray	Synonym		TRO
Penstemon globosus (Piper) Pennell & D.D. Keck	Accepted		TRO
Penstemon gloxinioides hort.	Unresolved		TRO
Penstemon goodrichii N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon gordonianus A.Gray	Unresolved		WCSP (in review)
Penstemon gordonii Hook.	Unresolved		WCSP (in review)
Penstemon gormanii Greene	Accepted		WCSP (in review)
Penstemon gracilentus A.Gray	Unresolved		WCSP (in review)
Penstemon gracilis Nutt.	Accepted		WCSP (in review)
Penstemon gracilis subsp. wisconsinensis (Pennell) Pennell	Synonym		TRO
Penstemon gracilis var. wisconsinensis (Pennell) R.W. Benn.	Accepted		TRO
Penstemon grahamii D.D.Keck	Unresolved		WCSP (in review)
Penstemon grandiflorus Nutt.	Accepted		WCSP (in review)
Penstemon griffinii A.Nelson	Unresolved		WCSP (in review)
Penstemon grinnellii Eastw.	Synonym		TRO
Penstemon grinnellii subsp. scrophularioides (M.E. Jones) Munz	Synonym		TRO
Penstemon grinnellii var. scrophularioides (M.E. Jones) N.H. Holmgren	Unresolved		TRO
Penstemon guadalupensis A.Heller	Unresolved		WCSP (in review)
Penstemon guadalupensis subsp. ernestii Pennell	Synonym		TRO
Penstemon guadalupensis var. ernestii (Pennell) Cory	Unresolved		TRO
Penstemon hallii A.Gray	Unresolved		WCSP (in review)
Penstemon hallii var. arizonicus A. Gray	Synonym		TRO
Penstemon hansonii A.Nelson	Unresolved		WCSP (in review)
Penstemon harbourii A.Gray	Unresolved		WCSP (in review)
Penstemon harringtonii Penland	Unresolved		WCSP (in review)
Penstemon hartwegii Benth.	Accepted		TRO
Penstemon havardii A.Gray	Unresolved		WCSP (in review)
Penstemon haydenii S.Watson ex J.M.Coult.	Unresolved		WCSP (in review)
Penstemon haydenii S.Watson	Unresolved		WCSP (in review)
Penstemon helleri Small	Unresolved		WCSP (in review)
Penstemon henricksonii Straw	Accepted		TRO
Penstemon hesperius Peck	Unresolved		WCSP (in review)
Penstemon heterander Torr. & A. Gray	Synonym		TRO
Penstemon heterodoxus A.Gray	Unresolved		WCSP (in review)
Penstemon heterodoxus subsp. cephalophorus (Greene) D.D. Keck	Synonym		TRO
Penstemon heterodoxus var. cephalophorus (Greene) N.H. Holmgren	Unresolved		TRO
Penstemon heterodoxus var. shastensis (D.D. Keck) N.H. Holmgren	Unresolved		TRO
Penstemon heterophyllus Lindl.	Unresolved		WCSP (in review)
Penstemon heterophyllus S.Watson	Unresolved		WCSP (in review)
Penstemon heterophyllus subsp. australis (Munz & I.M. Johnst.) D.D. Keck	Unresolved		TRO
Penstemon heterophyllus var. australis Munz & I.M. Johnst.	Synonym		TRO
Penstemon heterophyllus var. azureus (Benth.) Jeps.	Unresolved		TRO
Penstemon heterophyllus subsp. purdyi D.D. Keck	Synonym		TRO
Penstemon heterophyllus var. purdyi (D.D. Keck) McMinn	Unresolved		TRO
Penstemon heterophyllus subsp. spinulosus (Wooton & Standl.) D.D. Keck	Unresolved		TRO
Penstemon hians I.M.Johnst.	Unresolved		WCSP (in review)
Penstemon hidalgensis Straw	Accepted		TRO
Penstemon higginsii (Neese) N.H. Holmgren & N.D. Atwood	Accepted		TRO
Penstemon hintonii Straw	Unresolved		WCSP (in review)
Penstemon hirsutus (L.) Willd.	Accepted		TRO
Penstemon holmgrenii S.L.Clark	Unresolved		WCSP (in review)
Penstemon humboldtii G.Don	Unresolved		WCSP (in review)
Penstemon humilis Nutt. ex A.Gray	Unresolved		WCSP (in review)
Penstemon humilis subsp. brevifolius (A. Gray) D.D. Keck	Unresolved		TRO
Penstemon humilis var. brevifolius A. Gray	Synonym		TRO
Penstemon humilis subsp. obtusifolius (Pennell) D.D. Keck	Synonym		TRO
Penstemon humilis var. obtusifolius (Pennell) Reveal	Unresolved		TRO
Penstemon × hybridus Voss	Unresolved		WCSP (in review)
Penstemon idahoensis N.D.Atwood & S.L.Welsh	Unresolved		WCSP (in review)
Penstemon ilicifolius Nutt. ex Benth.	Unresolved		WCSP (in review)
Penstemon imberbis (Kunth) Trautv.	Accepted		TRO
Penstemon immanifestus N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon incanus (A. Gray) Tidestr.	Accepted		TRO
Penstemon incertus Brandegee	Synonym		TRO
Penstemon inermis Poir.	Unresolved		WCSP (in review)
Penstemon inflatus Crosswh.	Unresolved		WCSP (in review)
Penstemon interruptus Greene	Unresolved		WCSP (in review)
Penstemon intonsus A.Heller	Unresolved		WCSP (in review)
Penstemon isophyllus B.L. Rob.	Accepted		TRO
Penstemon jacintensis Abrams	Synonym		TRO
Penstemon jaffrayanus Hook.	Unresolved		WCSP (in review)
Penstemon jaffrayanus var. parvulus (A. Gray) Jeps.	Synonym		TRO
Penstemon jaliscensis B.L. Rob.	Unresolved		TRO
Penstemon jamesii Benth.	Accepted		TRO
Penstemon jamesii subsp. breviculus D.D. Keck	Synonym		TRO
Penstemon jamesii subsp. ophianthus (Pennell) D.D. Keck	Accepted		TRO
Penstemon janishiae N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon jeffreyanus A.Murray bis	Unresolved		WCSP (in review)
Penstemon jonesii Pennell	Unresolved		WCSP (in review)
Penstemon keckii Clokey	Synonym		TRO
Penstemon kennedyi A. Nelson	Synonym		TRO
Penstemon kingii S.Watson	Unresolved		WCSP (in review)
Penstemon kleei Greene	Synonym		TRO
Penstemon kunthii G. Don	Accepted		TRO
Penstemon labrosus (A. Gray) Hook. f.	Accepted		TRO
Penstemon lacerellus Greene	Unresolved		WCSP (in review)
Penstemon laetus subsp. filiformis D.D. Keck	Synonym		TRO
Penstemon laetus var. filiformis (D.D. Keck) McMinn	Synonym		TRO
Penstemon laetus subsp. leptosepalus (Greene ex A. Gray) D.D. Keck	Unresolved		TRO
Penstemon laetus var. leptosepalus Greene ex A. Gray	Synonym		TRO
Penstemon laetus subsp. roezlii (Regel) D.D. Keck	Unresolved		TRO
Penstemon laetus var. roezlii (Regel) Jeps.	Synonym		TRO
Penstemon laetus subsp. sagittatus D.D. Keck	Synonym		TRO
Penstemon laetus var. sagittatus (D.D. Keck) McMinn	Unresolved		TRO
Penstemon laevigatus Aiton	Unresolved		WCSP (in review)
Penstemon laevigatus subsp. alluviorum (Pennell) R.W. Benn.	Unresolved		TRO
Penstemon laevigatus var. calycosus (Small) Farw.	Synonym		TRO
Penstemon laevigatus subsp. calycosus (Small) R.W. Benn.	Unresolved		TRO
Penstemon laevigatus var. canescens Britton	Synonym		TRO
Penstemon laevigatus var. deamii (Pennell) R.W. Benn.	Unresolved		TRO
Penstemon laevigatus subsp. digitalis (Nutt. ex Sims) R.W. Benn.	Unresolved		TRO
Penstemon laevis Pennell	Unresolved		WCSP (in review)
Penstemon lanceolatus Benth.	Accepted		TRO
Penstemon laricifolius Hook. & Arn.	Unresolved		WCSP (in review)
Penstemon laricifolius subsp. exilifolius (A. Nelson) D.D. Keck	Unresolved		TRO
Penstemon laricifolius var. exilifolius (A. Nelson) Payson	Synonym		TRO
Penstemon lassenianus Greene	Unresolved		WCSP (in review)
Penstemon latifolius Hoffmanns.	Unresolved		WCSP (in review)
Penstemon latifolius Krautter	Unresolved		WCSP (in review)
Penstemon latiusculus Greene	Unresolved		WCSP (in review)
Penstemon laxiflorus Pennell	Synonym		TRO
Penstemon laxus A. Nelson	Synonym		TRO
Penstemon leiophyllus Pennell	Unresolved		WCSP (in review)
Penstemon leiophyllus var. francisci-pennellii (Crosswh.) N.H. Holmgren	Unresolved		TRO
Penstemon leiophyllus var. keckii (Clokey) N.H. Holmgren	Unresolved		TRO
Penstemon lemhiensis (D.D. Keck) D.D. Keck & Cronquist	Accepted		TRO
Penstemon lemmonii A. Gray	Synonym		TRO
Penstemon lentus Pennell	Unresolved		WCSP (in review)
Penstemon lentus subsp. albiflorus D.D. Keck	Synonym		TRO
Penstemon lentus var. albiflorus (D.D. Keck) Reveal	Unresolved		TRO
Penstemon leonardii Rydb.	Unresolved		WCSP (in review)
Penstemon leonardii var. higginsii Neese	Synonym		TRO
Penstemon leonardii var. patricus (N.H. Holmgren) Neese	Unresolved		TRO
Penstemon leonensis Straw	Accepted		TRO
Penstemon leptanthus Pennell	Unresolved		WCSP (in review)
Penstemon leptophyllus Rydb.	Unresolved		WCSP (in review)
Penstemon leucanthus Greene	Unresolved		WCSP (in review)
Penstemon lewisii Benth.	Unresolved		WCSP (in review)
Penstemon linarioides A. Gray	Accepted		TRO
Penstemon linarioides var. californicus Munz & I.M. Johnst.	Synonym		TRO
Penstemon linarioides subsp. coloradoensis (A. Nelson) D.D. Keck	Accepted		TRO
Penstemon linarioides subsp. maguirei D.D. Keck	Synonym		TRO
Penstemon linarioides var. maguirei (D.D. Keck) A. Nelson	Accepted		TRO
Penstemon linarioides var. seorsus A. Nelson	Synonym		TRO
Penstemon linarioides subsp. sileri (A. Gray) D.D. Keck	Accepted		TRO
Penstemon linarioides var. sileri A. Gray	Synonym		TRO
Penstemon linarioides subsp. taosensis D.D. Keck	Synonym		TRO
Penstemon linearifolius J.M.Coult. & Fisher	Unresolved		WCSP (in review)
Penstemon lineolatus Greene	Unresolved		WCSP (in review)
Penstemon lobbii Lem.	Unresolved		WCSP (in review)
Penstemon longiflorus (Pennell) S.L. Clark	Accepted		TRO
Penstemon longifolius Scheele	Unresolved		WCSP (in review)
Penstemon luteus G.L. Nesom	Accepted		TRO
Penstemon lyallii (A.Gray) A.Gray	Unresolved		WCSP (in review)
Penstemon macbridei A.Nelson	Unresolved		WCSP (in review)
Penstemon × macewanii Paxton	Unresolved		WCSP (in review)
Penstemon mackayanus Knowles & Westc.	Unresolved		WCSP (in review)
Penstemon macranthus Eastw.	Synonym		TRO
Penstemon magnus Pennell	Synonym		TRO
Penstemon maguirei Crosswh.	Unresolved		WCSP (in review)
Penstemon marcusii (D.D. Keck) N.H. Holmgren	Accepted		TRO
Penstemon mensarum Pennell	Unresolved		WCSP (in review)
Penstemon menziesii Hook.	Unresolved		WCSP (in review)
Penstemon menziesii subsp. davaidsonii (Greene) Pennell & D.D. Keck	Unresolved		TRO
Penstemon menziesii subsp. davidsonii (Greene) Piper	Synonym		TRO
Penstemon menziesii var. davidsonii (Greene) Piper	Synonym		TRO
Penstemon metcalfei Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon mexicanus hort. ex Lindl.	Synonym		TRO
Penstemon microphyllus A. Gray	Synonym		TRO
Penstemon militaris Greene	Synonym		TRO
Penstemon miniatus Lindl.	Accepted		TRO
Penstemon minidokanus A.Nelson & J.F.Macbr.	Unresolved		WCSP (in review)
Penstemon minor (A. Gray) D.D. Keck	Accepted		TRO
Penstemon minutifolius Straw	Unresolved		TRO
Penstemon mirus A.Nelson	Unresolved		WCSP (in review)
Penstemon miser A.Gray	Unresolved		WCSP (in review)
Penstemon modestus Greene	Synonym		TRO
Penstemon moffatii Eastw.	Unresolved		WCSP (in review)
Penstemon moffatii subsp. marcusii D.D. Keck	Synonym		TRO
Penstemon moffatii subsp. paysonii (Pennell) D.D. Keck	Unresolved		TRO
Penstemon mohinoranus Straw	Accepted		TRO
Penstemon montanus Greene	Unresolved		WCSP (in review)
Penstemon montanus subsp. idahoensis D.D. Keck	Synonym		TRO
Penstemon montanus var. idahoensis (D.D. Keck) Cronquist	Unresolved		TRO
Penstemon moriahensis N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon moronensis Crosswh.	Unresolved		WCSP (in review)
Penstemon mucronatus N.H. Holmgren	Synonym		TRO
Penstemon multicaulis Pennell	Unresolved		WCSP (in review)
Penstemon multiflorus (Benth.) Chapm. ex Small	Accepted		TRO
Penstemon munzii I.M.Johnst.	Unresolved		WCSP (in review)
Penstemon murrayanus Hook.	Unresolved		WCSP (in review)
Penstemon nanus D.D.Keck	Unresolved		WCSP (in review)
Penstemon navajoa N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon nelsoniae D.D.Keck & Thomps.	Unresolved		WCSP (in review)
Penstemon nemorosus (Douglas ex Lindl.) Trautv.	Synonym		WCSP (in review)
Penstemon neomexicanus Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon neotericus D.D.Keck	Unresolved		WCSP (in review)
Penstemon newberryi A.Gray	Unresolved		WCSP (in review)
Penstemon newberryi subsp. berryi (Eastw.) D.D. Keck	Synonym		TRO
Penstemon newberryi var. berryi (Eastw.) N.H. Holmgren	Unresolved		TRO
Penstemon newberryi var. rupicola Piper	Synonym		TRO
Penstemon newberryi subsp. sonomensis (Greene) D.D. Keck	Unresolved		TRO
Penstemon newberryi var. sonomensis (Greene) Jeps.	Synonym		TRO
Penstemon nitidus Douglas ex Benth.	Accepted		WCSP (in review)
Penstemon nitidus subsp. polyphyllus Pennell	Synonym		TRO
Penstemon nitidus var. polyphyllus (Pennell) Cronquist	Accepted		TRO
Penstemon nudiflorus A.Gray	Unresolved		WCSP (in review)
Penstemon nuttallii L.C.Beck	Unresolved		WCSP (in review)
Penstemon nyeensis Crosswh.	Unresolved		WCSP (in review)
Penstemon obtusifolius Pennell	Synonym		TRO
Penstemon occiduus Straw	Accepted		TRO
Penstemon oklahomensis Pennell	Unresolved		WCSP (in review)
Penstemon oliganthus Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon ophianthus Pennell	Synonym		TRO
Penstemon oreganus (A. Gray) Howell	Synonym		TRO
Penstemon oregonensis A.Murray bis	Unresolved		WCSP (in review)
Penstemon oreocharis Greene	Synonym		TRO
Penstemon oreophilus Rydb.	Unresolved		WCSP (in review)
Penstemon osterhoutii Pennell	Unresolved		WCSP (in review)
Penstemon ovatus Douglas	Unresolved		WCSP (in review)
Penstemon owenii A.Nelson	Unresolved		WCSP (in review)
Penstemon pachyphyllus A.Gray ex Rydb.	Unresolved		WCSP (in review)
Penstemon pachyphyllus subsp. congestus (M.E. Jones) D.D. Keck	Synonym		TRO
Penstemon pachyphyllus var. congestus (M.E. Jones) N.H. Holmgren	Unresolved		TRO
Penstemon pachyphyllus var. mucronatus (N.H. Holmgren) Neese	Unresolved		TRO
Penstemon pallescens Osterh.	Unresolved		WCSP (in review)
Penstemon pallidus Small	Accepted		TRO
Penstemon pallidus subsp. arkansanus (Pennell) R.W. Benn.	Accepted		TRO
Penstemon palmeri A.Gray	Unresolved		WCSP (in review)
Penstemon palmeri var. bicolor Brandegee	Synonym		TRO
Penstemon palmeri subsp. eglandulosus D.D. Keck	Synonym		TRO
Penstemon palmeri var. eglandulosus (D.D. Keck) N.H. Holmgren	Unresolved		TRO
Penstemon palmeri var. grinnellii (Eastw.) Munz & I.M. Johnst.	Unresolved		TRO
Penstemon palmeri var. macranthus (Eastw.) N.H. Holmgren	Unresolved		TRO
Penstemon palustris Pennell	Synonym		TRO
Penstemon pandus (A. Nelson & J.F. Macbr.) A. Nelson & J.F. Macbr.	Accepted		TRO
Penstemon paniculatus Howell	Unresolved		WCSP (in review)
Penstemon papillatus J.T.Howell	Unresolved		WCSP (in review)
Penstemon × parishii Davidson	Unresolved		WCSP (in review)
Penstemon parishii A.Gray	Unresolved		WCSP (in review)
Penstemon parryi (A. Gray) A. Gray	Accepted		TRO
Penstemon parviflorus Pennell	Unresolved		WCSP (in review)
Penstemon parvulus (A. Gray) Krautter	Synonym		TRO
Penstemon parvus Pennell	Unresolved		WCSP (in review)
Penstemon patens (M.E. Jones) N.H. Holmgren	Accepted		TRO
Penstemon patricus N.H. Holmgren	Synonym		TRO
Penstemon pauciflorus Greene	Unresolved		WCSP (in review)
Penstemon pauciflorus Buckley	Unresolved		WCSP (in review)
Penstemon payetensis A.Nelson & J.F.Macbr.	Unresolved		WCSP (in review)
Penstemon paysonii Pennell	Synonym		TRO
Penstemon paysoniorum D.D.Keck	Unresolved		WCSP (in review)
Penstemon peckii Pennell	Unresolved		WCSP (in review)
Penstemon peduncularis Nutt. ex Benth.	Unresolved		WCSP (in review)
Penstemon peirsonii Munz & I.M.Johnst.	Unresolved		WCSP (in review)
Penstemon penlandii W.A.Weber	Unresolved		WCSP (in review)
Penstemon pennellianus D.D.Keck	Unresolved		WCSP (in review)
Penstemon pentstemon (DC.) MacMill.	Accepted		TRO
Penstemon perfoliatus Brongn.	Accepted		TRO
Penstemon perpulcher A.Nelson	Unresolved		WCSP (in review)
Penstemon perpulcher var. pandus A. Nelson & J.F. Macbr.	Synonym		TRO
Penstemon personatus D.D.Keck	Unresolved		WCSP (in review)
Penstemon petiolatus Brandegee	Unresolved		WCSP (in review)
Penstemon phlogifolius Greene	Unresolved		WCSP (in review)
Penstemon pickettii H.St.John	Unresolved		WCSP (in review)
Penstemon pilifer A. Heller	Synonym		TRO
Penstemon piliferus A.Heller	Unresolved		WCSP (in review)
Penstemon pilosigulatus A.Nelson	Unresolved		WCSP (in review)
Penstemon pinetorum Piper	Unresolved		WCSP (in review)
Penstemon pinifolius Greene	Accepted		TRO
Penstemon pinorum L.M.Shultz & J.S.Shultz	Unresolved		WCSP (in review)
Penstemon plagapineus Straw	Accepted		TRO
Penstemon platyphyllus Rydb.	Unresolved		WCSP (in review)
Penstemon plummerae Abrams	Unresolved		WCSP (in review)
Penstemon pononii auct.	Unresolved		WCSP (in review)
Penstemon potosinus Straw	Unresolved		WCSP (in review)
Penstemon pratensis Greene	Unresolved		WCSP (in review)
Penstemon pringlei S.Watson	Unresolved		WCSP (in review)
Penstemon procerus Douglas ex Graham	Unresolved		WCSP (in review)
Penstemon procerus subsp. aberrans (M.E. Jones) D.D. Keck	Unresolved		TRO
Penstemon procerus var. aberrans (M.E. Jones) A. Nelson	Synonym		TRO
Penstemon procerus subsp. brachyanthus (Pennell) D.D. Keck	Synonym		TRO
Penstemon procerus var. brachyanthus (Pennell) Cronquist	Unresolved		TRO
Penstemon procerus subsp. formosus (A. Nelson) D.D. Keck	Synonym		TRO
Penstemon procerus var. formosus (A. Nelson) Cronquist	Unresolved		TRO
Penstemon procerus f. genuiculatus (Greene) L. Clark	Synonym		TRO
Penstemon procerus subsp. modestus (Greene) D.D. Keck	Synonym		TRO
Penstemon procerus var. modestus (Greene) N.H. Holmgren	Unresolved		TRO
Penstemon procerus var. tolmiei (Hook.) Cronquist	Unresolved		TRO
Penstemon procerus subsp. tolmiei (Hook.) D.D. Keck	Synonym		TRO
Penstemon procumbens Greene	Synonym		TRO
Penstemon productus Greene	Unresolved		WCSP (in review)
Penstemon propinquus Greene	Unresolved		WCSP (in review)
Penstemon pruinosus Douglas	Unresolved		WCSP (in review)
Penstemon pseudohumilis M.E.Jones	Unresolved		WCSP (in review)
Penstemon pseudohumilis Rydb.	Unresolved		WCSP (in review)
Penstemon pseudoparvus Crosswh.	Unresolved		WCSP (in review)
Penstemon pseudoprocerus Rydb.	Synonym		TRO
Penstemon pseudoputus (Crosswh.) N.H. Holmgren	Accepted		TRO
Penstemon pseudospectabilis M.E.Jones	Unresolved		WCSP (in review)
Penstemon pseudospectabilis subsp. connatifolius (A. Nelson) D.D. Keck	Unresolved		TRO
Penstemon puberulentus Rydb.	Unresolved		WCSP (in review)
Penstemon puberulus Wooton & Standl.	Unresolved		WCSP (in review)
Penstemon puberulus M.E.Jones	Unresolved		WCSP (in review)
Penstemon pubescens Aiton	Unresolved		WCSP (in review)
Penstemon pubescens var. gracilis (Nutt.) A. Gray	Synonym		TRO
Penstemon pubescens var. multiflorus Benth.	Synonym		TRO
Penstemon pudicus Reveal & Beatley	Unresolved		WCSP (in review)
Penstemon pulchellus Greene	Accepted		TRO
Penstemon pumilus Nutt.	Unresolved		WCSP (in review)
Penstemon pumilus var. incanus A. Gray	Synonym		TRO
Penstemon pumilus var. thompsoniae A. Gray	Synonym		TRO
Penstemon punctatus Brandegee	Accepted		TRO
Penstemon puniceus Lilja	Unresolved		WCSP (in review)
Penstemon puniceus A.Gray	Unresolved		WCSP (in review)
Penstemon puniceus var. parryi A. Gray	Synonym		TRO
Penstemon purpusii Brandegee	Unresolved		WCSP (in review)
Penstemon putus A.Nelson	Unresolved		WCSP (in review)
Penstemon radicosus A.Nelson	Unresolved		WCSP (in review)
Penstemon ramaleyi A.Nelson	Unresolved		WCSP (in review)
Penstemon ramosus Crosswh.	Unresolved		WCSP (in review)
Penstemon rattanii A.Gray	Unresolved		WCSP (in review)
Penstemon rattanii subsp. kleei (Greene) D.D. Keck	Unresolved		TRO
Penstemon rattanii var. kleei (Greene) A. Gray	Synonym		TRO
Penstemon rattanii var. minor A. Gray	Synonym		TRO
Penstemon recurvatus A.Heller	Unresolved		WCSP (in review)
Penstemon regalis A. Nelson	Synonym		TRO
Penstemon retrorsoides Crosswh.	Unresolved		TRO
Penstemon rex A.Nelson & J.F.Macbr.	Unresolved		WCSP (in review)
Penstemon rhizomatosus N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon richardsonii Douglas	Unresolved		WCSP (in review)
Penstemon richardsonii subsp. curtiflorus D.D. Keck	Synonym		TRO
Penstemon richardsonii var. curtiflorus (D.D. Keck) Cronquist	Unresolved		TRO
Penstemon richardsonii subsp. dentatus D.D. Keck	Synonym		TRO
Penstemon richardsonii var. dentatus (D.D. Keck) Cronquist	Unresolved		TRO
Penstemon riparius A. Nelson	Synonym		TRO
Penstemon rivularis Douglas ex Trautv.	Unresolved		WCSP (in review)
Penstemon roezlii Regel	Synonym		TRO
Penstemon roezlii var. violaceus Brandegee	Synonym		TRO
Penstemon roseus (Cerv. ex Sweet) G. Don	Accepted		TRO
Penstemon rostriflorus Kellogg	Accepted		TRO
Penstemon rothrockii A. Gray	Synonym		TRO
Penstemon rothrockii subsp. jacintensis (Abrams) D.D. Keck	Synonym		TRO
Penstemon rothrockii var. jacintensis (Abrams) Munz & I.M. Johnst.	Synonym		TRO
Penstemon rotundifolius A. Gray	Accepted		TRO
Penstemon rubescens A.Gray	Unresolved		WCSP (in review)
Penstemon rubicundus D.D.Keck	Unresolved		WCSP (in review)
Penstemon rupicola (Piper) Howell	Accepted		TRO
Penstemon rydbergii A.Nelson	Unresolved		WCSP (in review)
Penstemon rydbergii var. aggregatus (Pennell) N.H. Holmgren	Unresolved		TRO
Penstemon rydbergii subsp. aggregatus (Pennell) D.D. Keck	Synonym		TRO
Penstemon rydbergii var. oreocharis (Greene) N.H. Holmgren	Unresolved		TRO
Penstemon sagittatus (D.D.Keck) Pennell	Unresolved		WCSP (in review)
Penstemon saliens Rydb.	Synonym		TRO
Penstemon saltarius Crosswh.	Unresolved		WCSP (in review)
Penstemon saxosorum Pennell	Unresolved		WCSP (in review)
Penstemon scabridus Eastw.	Unresolved		WCSP (in review)
Penstemon scapoides D.D.Keck	Unresolved		WCSP (in review)
Penstemon scariosus var. albifluvis (England) N.H. Holmgren	Unresolved		TRO
Penstemon scariosus var. garrettii (Pennell) N.H. Holmgren	Unresolved		TRO
Penstemon schaffneri (Hemsl.) Straw	Unresolved		WCSP (in review)
Penstemon scoparius A.Nelson	Unresolved		WCSP (in review)
Penstemon scouleri Douglas ex Lindl.	Synonym		TRO
Penstemon scrophularioides M.E. Jones	Synonym		TRO
Penstemon secundiflorus Benth.	Accepted		TRO
Penstemon seorsus (A. Nelson) D.D. Keck	Accepted		TRO
Penstemon sepalulus A.Nelson	Unresolved		WCSP (in review)
Penstemon serrulatus Menzies	Unresolved		WCSP (in review)
Penstemon shantzii A.Nelson	Unresolved		WCSP (in review)
Penstemon shastensis D.D. Keck	Synonym		TRO
Penstemon shockleyi S.Watson	Unresolved		WCSP (in review)
Penstemon similis A.Nelson	Unresolved		WCSP (in review)
Penstemon skutchii Straw	Synonym		TRO
Penstemon smallii A.Heller	Unresolved		WCSP (in review)
Penstemon sonomensis Greene	Synonym		TRO
Penstemon spathulatus Eastw. ex C.F.Baker	Unresolved		WCSP (in review)
Penstemon spatulatus Pennell	Unresolved		WCSP (in review)
Penstemon speciosus Douglas	Unresolved		WCSP (in review)
Penstemon speciosus subsp. kennedyi (A. Nelson) D.D. Keck	Unresolved		TRO
Penstemon speciosus subsp. lemhiensis D.D. Keck	Synonym		TRO
Penstemon speciosus var. piliferus (A. Heller) Munz & I.M. Johnst.	Unresolved		TRO
Penstemon spectabilis Thurb. ex A. Gray	Accepted		TRO
Penstemon spectabilis var. subviscosis (D.D. Keck) McMinn	Accepted		TRO
Penstemon spectabilis subsp. subviscosus D.D. Keck	Synonym		TRO
Penstemon spicatus auct.	Unresolved		WCSP (in review)
Penstemon spinulosus Wooton & Standl.	Synonym		TRO
Penstemon staticifolius Lindl.	Unresolved		WCSP (in review)
Penstemon stenophyllus A. Gray	Accepted		TRO
Penstemon stenosepalus (A. Gray) Howell	Accepted		TRO
Penstemon stephensii Brandegee	Synonym		TRO
Penstemon strictiformis Rydb.	Synonym		TRO
Penstemon strictus Benth.	Unresolved		WCSP (in review)
Penstemon strictus subsp. strictiformis (Rydb.) D.D. Keck	Unresolved		TRO
Penstemon subglaber Rydb.	Unresolved		WCSP (in review)
Penstemon subserratus Pennell	Unresolved		WCSP (in review)
Penstemon subulatus M.E.Jones	Unresolved		WCSP (in review)
Penstemon sudans M.E. Jones	Synonym		TRO
Penstemon suffrutescens Rydb.	Unresolved		WCSP (in review)
Penstemon suffruticosus Douglas ex Benth.	Unresolved		WCSP (in review)
Penstemon superbus A.Nelson	Unresolved		WCSP (in review)
Penstemon tenellus Kellogg	Unresolved		WCSP (in review)
Penstemon tenuiflorus Pennell	Unresolved		WCSP (in review)
Penstemon tenuifolius Benth.	Accepted		TRO
Penstemon tenuis Small	Unresolved		WCSP (in review)
Penstemon tepicensis Straw	Accepted		TRO
Penstemon teretiflorus Nutt.	Unresolved		WCSP (in review)
Penstemon ternatus Torr. ex A. Gray	Synonym		TRO
Penstemon ternatus subsp. septentrionalis (Munz & I.M. Johnst.) D.D. Keck	Synonym		TRO
Penstemon ternatus var. septentrionalis Munz & I.M. Johnst.	Synonym		TRO
Penstemon teucrioides Greene	Unresolved		WCSP (in review)
Penstemon themisteri Bailly	Unresolved		WCSP (in review)
Penstemon thompsoniae (A. Gray) Rydb.	Accepted		TRO
Penstemon thurberi Torr.	Accepted		TRO
Penstemon tidestromii Pennell	Unresolved		WCSP (in review)
Penstemon tiehmii N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon tinctus Pennell	Unresolved		WCSP (in review)
Penstemon tolmiei Hook.	Synonym		TRO
Penstemon tolmiei subsp. brachyanthus (Pennell) D.D. Keck	Synonym		TRO
Penstemon tolmiei subsp. formosus (A. Nelson) D.D. Keck	Synonym		TRO
Penstemon torreyi Benth.	Synonym		TRO
Penstemon tracyi D.D.Keck	Unresolved		WCSP (in review)
Penstemon trichander (A. Gray) Rydb.	Synonym		TRO
Penstemon triflorus A. Heller	Accepted		TRO
Penstemon triphyllus Douglas	Unresolved		WCSP (in review)
Penstemon truncatus Pennell	Unresolved		WCSP (in review)
Penstemon tubaeflorus Nutt.	Unresolved		TRO
Penstemon tusharensis N.H.Holmgren	Unresolved		WCSP (in review)
Penstemon tweedyi Canby & Rose	Synonym		TRO
Penstemon uintahensis Pennell	Unresolved		WCSP (in review)
Penstemon unilateralis Rydb.	Unresolved		WCSP (in review)
Penstemon utahensis (S. Watson) A. Nelson	Accepted		TRO
Penstemon variabilis Suksd.	Synonym		TRO
Penstemon vaseyanus Greene	Unresolved		WCSP (in review)
Penstemon venosus (D.D. Keck) Reveal	Synonym		TRO
Penstemon venustus Douglas	Unresolved		WCSP (in review)
Penstemon veronicifolius Greene	Unresolved		WCSP (in review)
Penstemon versicolor Pennell	Unresolved		WCSP (in review)
Penstemon verticillatus M.Martens & Galeotti	Unresolved		WCSP (in review)
Penstemon violaceus (Brandegee) A. Nelson	Accepted		TRO
Penstemon virens Pennell ex Rydb.	Unresolved		WCSP (in review)
Penstemon virgatus A. Gray	Accepted		TRO
Penstemon virgatus var. arizonicus (A. Gray) D.D. Keck	Accepted		TRO
Penstemon virgatus subsp. asa-grayi Crosswh.	Synonym		TRO
Penstemon virgatus var. asa-grayi (Crosswh.) Dorn	Accepted		TRO
Penstemon virgatus subsp. pseudoputus Crosswh.	Synonym		TRO
Penstemon viscidulus Nees	Unresolved		WCSP (in review)
Penstemon vizcainensis Moran	Unresolved		WCSP (in review)
Penstemon vulcanellus Crosswh.	Unresolved		WCSP (in review)
Penstemon wardii A. Gray	Synonym		TRO
Penstemon washingtonensis D.D.Keck	Unresolved		WCSP (in review)
Penstemon washoensis Greene	Unresolved		WCSP (in review)
Penstemon watsonii A.Gray	Unresolved		WCSP (in review)
Penstemon watsonii subsp. laxus (A. Nelson) D.D. Keck	Unresolved		TRO
Penstemon wherryi Pennell	Unresolved		WCSP (in review)
Penstemon whippleanus A.Gray	Unresolved		WCSP (in review)
Penstemon whitedii Piper	Synonym		TRO
Penstemon whitedii subsp. dayanus (Howell) D.D. Keck	Unresolved		TRO
Penstemon willcoxii Rydb.	Unresolved		WCSP (in review)
Penstemon wisconsinensis Pennell	Synonym		TRO
Penstemon wislizenii (A. Gray) Straw	Accepted		TRO
Penstemon woodsii A.Nelson	Unresolved		WCSP (in review)
Penstemon wrightii Hook.	Unresolved		WCSP (in review)
Penstemon xylus A.Nelson	Unresolved		WCSP (in review)
Penstemon yampaensis Penland	Synonym		TRO