| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| PEAB | Penstemon abietinus Pennell | firleaf beardtongue | Scrophulariaceae
|
| PEAB2 | Penstemon absarokensis Evert | Absaroka Range beardtongue | Scrophulariaceae
|
| PEACY | Penstemon acaulis L.O. Williams var. yampaensis (Penl.) Neese | Penstemon yampaensis | Scrophulariaceae
|
| PEAC3 | Penstemon acaulis L.O. Williams | stemless beardtongue | Scrophulariaceae
|
| PEACA | Penstemon acuminatus Dougl. ex Lindl. var. acuminatus | sharpleaf penstemon | Scrophulariaceae
|
| PEACL | Penstemon acuminatus Dougl. ex Lindl. var. latebracteatus N. Holmgren | sharpleaf penstemon | Scrophulariaceae
|
| PEAC | Penstemon acuminatus Dougl. ex Lindl. | sharpleaf penstemon | Scrophulariaceae
|
| PEAG2 | Penstemon aggregatus Pennell | Penstemon rydbergii var. aggregatus | Scrophulariaceae
|
| PEAL10 | Penstemon alamosensis Pennell & Nisbet | Los Alamos beardtongue | Scrophulariaceae
|
| PEAL11 | Penstemon albertinus Greene | Alberta beardtongue | Scrophulariaceae
|
| PEAL2 | Penstemon albidus Nutt. | white penstemon | Scrophulariaceae
|
| PEAL80 | Penstemon albifluvis England | Penstemon scariosus var. albifluvis | Scrophulariaceae
|
| PEAL3 | Penstemon albomarginatus M.E. Jones | whitemargin beardtongue | Scrophulariaceae
|
| PEAL4 | Penstemon alluviorum Pennell | lowland beardtongue | Scrophulariaceae
|
| PEALB | Penstemon alpinus Torr. ssp. brandegeei (Porter) Penl. | Penstemon glaber var. brandegeei | Scrophulariaceae
|
| PEALM | Penstemon alpinus Torr. ssp. magnus (Pennell) Harrington | Penstemon glaber var. glaber | Scrophulariaceae
|
| PEAL5 | Penstemon alpinus Torr. | Penstemon glaber var. alpinus | Scrophulariaceae
|
| PEAML | Penstemon ambiguus Torr. ssp. laevissimus Keck | Penstemon ambiguus var. laevissimus | Scrophulariaceae
|
| PEAMA | Penstemon ambiguus Torr. var. ambiguus | gilia beardtongue | Scrophulariaceae
|
| PEAML2 | Penstemon ambiguus Torr. var. laevissimus (Keck) N. Holmgren | pink plains beardtongue | Scrophulariaceae
|
| PEAM | Penstemon ambiguus Torr. | gilia beardtongue | Scrophulariaceae
|
| PEAM5 | Penstemon ammophilus N. Holmgren & L. Shultz | sandloving penstemon | Scrophulariaceae
|
| PEAN3 | Penstemon anguineus Eastw. | Siskiyou beardtongue | Scrophulariaceae
|
| PEANC2 | Penstemon angustifolius Nutt. ex Pursh ssp. caudatus (Heller) Keck | Penstemon angustifolius var. caudatus | Scrophulariaceae
|
| PEANV3 | Penstemon angustifolius Nutt. ex Pursh ssp. venosus Keck | Penstemon angustifolius var. venosus | Scrophulariaceae
|
| PEANA2 | Penstemon angustifolius Nutt. ex Pursh var. angustifolius | broadbeard beardtongue | Scrophulariaceae
|
| PEANC | Penstemon angustifolius Nutt. ex Pursh var. caudatus (Heller) Rydb. | broadbeard beardtongue | Scrophulariaceae
|
| PEAND | Penstemon angustifolius Nutt. ex Pursh var. dulcis Neese | broadbeard beardtongue | Scrophulariaceae
|
| PEANV | Penstemon angustifolius Nutt. ex Pursh var. venosus (Keck) N. Holmgren | broadbeard beardtongue | Scrophulariaceae
|
| PEANV2 | Penstemon angustifolius Nutt. ex Pursh var. vernalensis N. Holmgren | broadbeard beardtongue | Scrophulariaceae
|
| PEAN4 | Penstemon angustifolius Nutt. ex Pursh | broadbeard beardtongue | Scrophulariaceae
|
| PEANM | Penstemon antirrhinoides Benth. ssp. microphyllus (Gray) Keck | Keckiella antirrhinoides ssp. microphylla | Scrophulariaceae
|
| PEAN10 | Penstemon antirrhinoides Benth. | Keckiella antirrhinoides ssp. antirrhinoides | Scrophulariaceae
|
| PEAR3 | Penstemon arenarius Greene | Nevada sanddune beardtongue | Scrophulariaceae
|
| PEAR | Penstemon arenicola A. Nels. | sand penstemon | Scrophulariaceae
|
| PEAR2 | Penstemon aridus Rydb. | stiffleaf penstemon | Scrophulariaceae
|
| PEARP | Penstemon arkansanus Pennell var. pubescens Pennell | Penstemon pallidus | Scrophulariaceae
|
| PEAR4 | Penstemon arkansanus Pennell | Arkansas beardtongue | Scrophulariaceae
|
| PEAS | Penstemon assurgens Keck | Penstemon attenuatus var. militaris | Scrophulariaceae
|
| PEATM | Penstemon attenuatus Dougl. ex Lindl. ssp. militaris (Greene) Keck | Penstemon attenuatus var. militaris | Scrophulariaceae
|
| PEATP | Penstemon attenuatus Dougl. ex Lindl. ssp. palustris (Pennell) Keck | Penstemon attenuatus var. palustris | Scrophulariaceae
|
| PEATP2 | Penstemon attenuatus Dougl. ex Lindl. ssp. pseudoprocerus (Rydb.) Keck | Penstemon attenuatus var. pseudoprocerus | Scrophulariaceae
|
| PEATA2 | Penstemon attenuatus Dougl. ex Lindl. var. attenuatus | sulphur penstemon | Scrophulariaceae
|
| PEATM2 | Penstemon attenuatus Dougl. ex Lindl. var. militaris (Greene) Cronq. | South Idaho penstemon | Scrophulariaceae
|
| PEATP4 | Penstemon attenuatus Dougl. ex Lindl. var. palustris (Pennell) Cronq. | sulphur beardtongue | Scrophulariaceae
|
| PEATP5 | Penstemon attenuatus Dougl. ex Lindl. var. pseudoprocerus (Rydb.) Cronq. | small penstemon | Scrophulariaceae
|
| PEAT3 | Penstemon attenuatus Dougl. ex Lindl. | sulphur penstemon | Scrophulariaceae
|
| PEAT4 | Penstemon atwoodii Welsh | Kaiparowits beardtongue | Scrophulariaceae
|
| PEAU2 | Penstemon auriberbis Pennell | Colorado beardtongue | Scrophulariaceae
|
| PEAUL | Penstemon australis Small ssp. laxiflorus (Pennell) Bennett | Penstemon laxiflorus | Scrophulariaceae
|
| PEAUA2 | Penstemon australis Small var. ameles Crosswhite | Penstemon laxiflorus | Scrophulariaceae
|
| PEAU | Penstemon australis Small | Eustis Lake beardtongue | Scrophulariaceae
|
| PEAZA | Penstemon azureus Benth. ssp. angustissimus (Gray) Keck | azure penstemon | Scrophulariaceae
|
| PEAZA2 | Penstemon azureus Benth. ssp. azureus | azure penstemon | Scrophulariaceae
|
| PEAZA3 | Penstemon azureus Benth. var. angustissimus Gray | Penstemon azureus ssp. angustissimus | Scrophulariaceae
|
| PEAZP | Penstemon azureus Benth. var. parvulus Gray | Penstemon azureus ssp. azureus | Scrophulariaceae
|
| PEAZ | Penstemon azureus Benth. | azure penstemon | Scrophulariaceae
|
| PEBA | Penstemon baccharifolius Hook. | baccharisleaf beardtongue | Scrophulariaceae
|
| PEBAB | Penstemon barbatus (Cav.) Roth ssp. barbatus | beardlip penstemon | Scrophulariaceae
|
| PEBAT | Penstemon barbatus (Cav.) Roth ssp. torreyi (Benth.) Keck | Torrey's penstemon | Scrophulariaceae
|
| PEBAT2 | Penstemon barbatus (Cav.) Roth ssp. trichander (Gray) Keck | beardlip penstemon | Scrophulariaceae
|
| PEBAP | Penstemon barbatus (Cav.) Roth var. puberulus Gray | Penstemon barbatus ssp. barbatus | Scrophulariaceae
|
| PEBAT3 | Penstemon barbatus (Cav.) Roth var. torreyi (Benth.) Gray | Penstemon barbatus ssp. torreyi | Scrophulariaceae
|
| PEBAT4 | Penstemon barbatus (Cav.) Roth var. trichander Gray | Penstemon barbatus ssp. trichander | Scrophulariaceae
|
| PEBA2 | Penstemon barbatus (Cav.) Roth | beardlip penstemon | Scrophulariaceae
|
| PEBA6 | Penstemon barnebyi N. Holmgren | White River Valley beardtongue | Scrophulariaceae
|
| PEBA7 | Penstemon barrettiae Gray | Barrett's beardtongue | Scrophulariaceae
|
| PEBIB2 | Penstemon bicolor (Brandeg.) Clokey & Keck ssp. bicolor | pinto beardtongue | Scrophulariaceae
|
| PEBIR | Penstemon bicolor (Brandeg.) Clokey & Keck ssp. roseus Clokey & Keck | pinto beardtongue | Scrophulariaceae
|
| PEBI2 | Penstemon bicolor (Brandeg.) Clokey & Keck | pinto beardtongue | Scrophulariaceae
|
| PEBR8 | Penstemon bracteatus Keck | Red Canyon beardtongue | Scrophulariaceae
|
| PEBR14 | Penstemon bradburii Pursh | Penstemon grandiflorus | Scrophulariaceae
|
| PEBR13 | Penstemon brandegeei (Porter) Porter ex Rydb. | Penstemon glaber var. brandegeei | Scrophulariaceae
|
| PEBR12 | Penstemon brevibarbatus Crosswhite | Penstemon jamesii | Scrophulariaceae
|
| PEBR9 | Penstemon breviculus (Keck) Nisbet & R.C. Jackson | shortstem beardtongue | Scrophulariaceae
|
| PEBRG | Penstemon breviflorus Lindl. ssp. glabrisepalus Keck | Keckiella breviflora ssp. glabrisepala | Scrophulariaceae
|
| PEBR15 | Penstemon breviflorus Lindl. | Keckiella breviflora ssp. breviflora | Scrophulariaceae
|
| PEBR10 | Penstemon brevisepalus Pennell | Penstemon pallidus | Scrophulariaceae
|
| PEBRA2 | Penstemon bridgesii Gray var. amplexicaulis Monnet | Penstemon rostriflorus | Scrophulariaceae
|
| PEBR7 | Penstemon bridgesii Gray | Penstemon rostriflorus | Scrophulariaceae
|
| PEBR19 | Penstemon brittoniorum Pennell | Penstemon canescens | Scrophulariaceae
|
| PEBR17 | Penstemon bryantiae Keck | Bryant's beardtongue | Scrophulariaceae
|
| PEBU | Penstemon buckleyi Pennell | Buckley's beardtongue | Scrophulariaceae
|
| PECA3 | Penstemon caesius Gray | San Bernardino beardtongue | Scrophulariaceae
|
| PECAD | Penstemon caespitosus Nutt. ex Gray ssp. desertipicti (A. Nels.) Keck | Penstemon caespitosus var. desertipicti | Scrophulariaceae
|
| PECAP | Penstemon caespitosus Nutt. ex Gray ssp. perbrevis Pennell | Penstemon caespitosus var. perbrevis | Scrophulariaceae
|
| PECAC4 | Penstemon caespitosus Nutt. ex Gray var. caespitosus | mat penstemon | Scrophulariaceae
|
| PECAD2 | Penstemon caespitosus Nutt. ex Gray var. desertipicti (A. Nels.) N. Holmgren | mat penstemon | Scrophulariaceae
|
| PECAP2 | Penstemon caespitosus Nutt. ex Gray var. perbrevis (Pennell) N. Holmgren | mat penstemon | Scrophulariaceae
|
| PECAS | Penstemon caespitosus Nutt. ex Gray var. suffruticosus Gray | Penstemon tusharensis | Scrophulariaceae
|
| PECA4 | Penstemon caespitosus Nutt. ex Gray | mat penstemon | Scrophulariaceae
|
| PECA5 | Penstemon calcareus Brandeg. | limestone beardtongue | Scrophulariaceae
|
| PECA6 | Penstemon californicus (Munz & Johnston) Keck | California penstemon | Scrophulariaceae
|
| PECA7 | Penstemon calycosus Small | longsepal beardtongue | Scrophulariaceae
|
| PECA80 | Penstemon campanulatus (Cav.) Willd. | bellflower beardtongue | Scrophulariaceae
|
| PECAB | Penstemon canescens (Britt.) Britt. var. brittoniorum (Pennell) Pennell | Penstemon canescens | Scrophulariaceae
|
| PECAT | Penstemon canescens (Britt.) Britt. var. typicus Pennell | Penstemon canescens | Scrophulariaceae
|
| PECA8 | Penstemon canescens (Britt.) Britt. | eastern gray beardtongue | Scrophulariaceae
|
| PECAC5 | Penstemon cardinalis Woot. & Standl. ssp. cardinalis | cardinal beardtongue | Scrophulariaceae
|
| PECAR | Penstemon cardinalis Woot. & Standl. ssp. regalis (A. Nels.) Nisbet & R.C. Jackson | cardinal beardtongue | Scrophulariaceae
|
| PECA15 | Penstemon cardinalis Woot. & Standl. | cardinal beardtongue | Scrophulariaceae
|