| Entry | Volume | Pages |
|---|---|---|
| Penstemon | 62 | 158-80 |
| Penstemon 'Puyallup Pink' | 80 | 343C |
| Penstemon absarokensis | 62 | 172, 472 |
| Penstemon absarokensis | 75 | 524P.C., 525C |
| Penstemon acaulis | 15 | 27 |
| Penstemon acaulis | 40 | 185P, 187 |
| Penstemon acaulis | 62 | 165, 166 |
| Penstemon acaulis | 63 | 60 |
| Penstemon acaulis | 65 | 60, 63 |
| Penstemon acuminatus | 52 | 149 |
| Penstemon aggregatus | 27 | 211 |
| Penstemon alamosensis | 62 | 177 |
| Penstemon albertinus | 53 | 250 |
| Penstemon albertinus | 62 | 161 |
| Penstemon albidus | 53 | 247 |
| Penstemon albidus | 62 | 168 |
| Penstemon albomarginalis | 10 | 18 |
| Penstemon albomarginatus | 62 | 164 |
| Penstemon allbrightii | 62 | 162 |
| Penstemon alluviorum | 62 | 159 |
| Penstemon alpinus | 9 | 10P, 12 |
| Penstemon alpinus | 48 | 338 |
| Penstemon alpinus | 62 | 171 |
| Penstemon ambiguus | 10 | 170 |
| Penstemon ambiguus | 62 | 166, 474 |
| Penstemon ambiguus var. laevissimus | 62 | 166 |
| Penstemon 'Amethyst' | 23 | 56 |
| Penstemon anguineus | 62 | 162 |
| Penstemon angustifolius | 48 | 338 |
| Penstemon angustifolius | 62 | 175 |
| Penstemon angustifolius var. angustifolius | 62 | 175 |
| Penstemon angustifolius var. caudatus | 62 | 175 |
| Penstemon angustifolius var. venosus | 62 | 175 |
| Penstemon angustifolius var. vernalensis | 62 | 175 |
| Penstemon antirrhinoides | 10 | 79 |
| Penstemon antirrhinoides | 18 | 41 |
| Penstemon apateticus | 62 | 175 |
| Penstemon arenarius | 62 | 164 |
| Penstemon arenicola | 62 | 175 |
| Penstemon aridus | 6 | 361 |
| Penstemon aridus | 41 | 252 |
| Penstemon aridus | 48 | 332 |
| Penstemon aridus | 62 | 161 |
| Penstemon arkansanus | 62 | 159 |
| Penstemon atropurpureus | 62 | 175 |
| Penstemon attenuatus | 62 | 160 |
| Penstemon attenuatus subsp. pseudoprocerus | 62 | 160 |
| Penstemon atwoodii | 62 | 170 |
| Penstemon auriberbis | 16 | 15 |
| Penstemon auriberbis | 62 | 169 |
| Penstemon australis | 62 | 159 |
| Penstemon azureus | 62 | 178 |
| Penstemon azureus | 78 | 407 |
| Penstemon baccharifolius | 18 | 37 |
| Penstemon baccharifolius | 22 | 309 |
| Penstemon baccharifolius | 62 | 180 |
| Penstemon barbatus | 4 | 333 |
| Penstemon barbatus | 29 | R 21 |
| Penstemon barbatus | 62 | 174 |
| Penstemon barbatus 'Gussie Schooley' | 62 | 472 |
| Penstemon barbatus var. praecox | 62 | 174 |
| Penstemon barbatus subsp. torreyi | 62 | 174 |
| Penstemon barbatus subsp. trichlander | 62 | 174 |
| Penstemon barbatus var. wislizenii | 62 | 174 |
| Penstemon barnebyi | 58 | 255 |
| Penstemon barrettiae | 4 | 324, 331P, 332P |
| Penstemon barrettiae | 10 | 42 |
| Penstemon barrettiae | 41 | 248 |
| Penstemon barrettiae | 62 | 467C |
| Penstemon barrettiae 'Gina' | 62 | 472 |
| Penstemon bicolor | 62 | 177 |
| Penstemon 'Blackbird' | 74 | 29 |
| Penstemon bracteatus | 16 | 19 |
| Penstemon bracteatus | 62 | 176 |
| Penstemon bracteatus | 64 | 81 |
| Penstemon bradburii | 62 | 176 |
| Penstemon brandegei | 62 | 171 |
| Penstemon 'Breitenbush Blue' | 62 | 471 |
| Penstemon breviculus | 62 | 169 |
| Penstemon brevisepalus | 62 | 159 |
| Penstemon bridgesii | 4 | 333 |
| Penstemon bridgesii | 9 | 350 |
| Penstemon bridgesii | 49 | 69 |
| Penstemon bridgesii | 54 | 318, 319, 320, 322 |
| Penstemon bridgesii | 62 | 175 |
| Penstemon buckleyi | 62 | 176 |
| Penstemon caesius | 15 | 184 |
| Penstemon caesius | 62 | 178 |
| Penstemon caespitosus | 8 | 300 |
| Penstemon caespitosus | 16 | 10P, 22 |
| Penstemon caespitosus | 29 | R 21 |
| Penstemon caespitosus | 62 | 165, 167C |
| Penstemon caespitosus var. caespitosus | 62 | 165 |
| Penstemon caespitosus var. desertipicti | 40 | 187 |
| Penstemon caespitosus var. desertipicti | 62 | 165 |
| Penstemon caespitosus var. desertipicti | 64 | 82 |
| Penstemon caespitosus var. perbrevis | 27 | 213 |
| Penstemon caespitosus var. perbrevis | 62 | 165 |
| Penstemon caespitosus var. suffruticosus | 29 | R 21 |
| Penstemon caespitosus var. suffruticosus | 62 | 165 |
| Penstemon calcareus | 10 | 22 |
| Penstemon calcareus | 62 | 170 |
| Penstemon calcareus | 67 | 414 |
| Penstemon californicus | 70 | 26 |
| Penstemon californicus | 74 | 28C |
| Penstemon calycosus | 62 | 159 |
| Penstemon campanulatus | 4 | 333 |
| Penstemon campanulatus | 62 | 175 |
| Penstemon campanulatus var. chihuahensis | 62 | 175 |
| Penstemon campanulatus var. pulchellus | 48 | 26 |
| Penstemon campanulatus var. pulchellus | 51 | 48 |
| Penstemon canescens | 4 | 326 |
| Penstemon canescens | 62 | 160 |
| Penstemon cardinalis | 19 | 71 |
| Penstemon cardinalis | 62 | 175, 475 |
| Penstemon cardwellii | 48 | 156 |
| Penstemon cardwellii | 62 | 467 |
| Penstemon cardwellii | 64 | 82 |
| Penstemon cardwellii | 4 | 324 |
| Penstemon cardwellii 'Alba' | 62 | 472 |
| Penstemon cardwellii 'John Bacher' | 62 | 472 |
| Penstemon cardwellii 'Roseus' | 62 | 472 |
| Penstemon 'Carol' | 62 | 471 |
| Penstemon caryi | 62 | 171 |
| Penstemon centranthifolius | 4 | 333 |
| Penstemon centranthifolius | 62 | 177 |
| Penstemon cerrosensis | 62 | 177 |
| Penstemon cinereus | 62 | 162 |
| Penstemon cinicola | 62 | 161 |
| Penstemon cleburnei | 16 | 27 |
| Penstemon cleburnei | 62 | 169 |
| Penstemon clevelandii | 62 | 177 |
| Penstemon clevelandii var. connatus | 62 | 177 |
| Penstemon clutei | 17 | 65 |
| Penstemon cobaea | 62 | 168 |
| Penstemon cobaea subsp. purpureus | 62 | 168 |
| Penstemon coccineus | 62 | 174 |
| Penstemon coeruleo-purpureus | 4 | 325 |
| Penstemon coeruleo-purpureus | 20 | 115 |
| Penstemon coeruleo-purpureus ochroleucus | 4 | 325 |
| Penstemon coeruleo-purpureus violaceus | 4 | 325 |
| Penstemon coloradensis | 23 | 355 |
| Penstemon comarrhenus | 62 | 172 |
| Penstemon concinnus | 62 | 170 |
| Penstemon confertus | 4 | 325, 334 |
| Penstemon confertus | 25 | 39 |
| Penstemon confertus | 51 | 352 |
| Penstemon confertus | 53 | 177 |
| Penstemon confertus | 62 | 160C, 161 |
| Penstemon confusus | 62 | 177 |
| Penstemon cordifolius | 4 | 333 |
| Penstemon crandallii | 9 | 350 |
| Penstemon crandallii | 62 | 165 |
| Penstemon crandallii var. attratus | 62 | 165 |
| Penstemon crandallii subsp. glabrescens | 58 | 45 |
| Penstemon crandallii subsp. glabrescens | 64 | 81, 85 |
| Penstemon crandallii var. procumbens | 62 | 166 |
| Penstemon crassifolius | 4 | 323 |
| Penstemon crassifolius | 4 | 323 |
| Penstemon cristatus | 2 | 9 |
| Penstemon cristatus | 3 | 52 |
| Penstemon 'Crystal' | 62 | 471 |
| Penstemon cusickii | 62 | 178 |
| Penstemon cyananthus | 5 | 203 |
| Penstemon cyananthus | 7 | 202 |
| Penstemon cyananthus | 62 | 171, 172 |
| Penstemon cyananthus subsp. compactus | 62 | 172 |
| Penstemon cyaneus | 7 | 202 |
| Penstemon cyaneus | 52 | 149 |
| Penstemon cyaneus | 62 | 172 |
| Penstemon cyanocaulis | 62 | 172 |
| Penstemon cyathophorus | 62 | 176 |
| Penstemon dasyphyllus | 62 | 180 |
| Penstemon davidsonii | 2 | 9 |
| Penstemon davidsonii | 3 | 52, 295 |
| Penstemon davidsonii | 4 | 330 |
| Penstemon davidsonii | 10 | 42 |
| Penstemon davidsonii | 11 | 237 |
| Penstemon davidsonii | 17 | 65 |
| Penstemon davidsonii | 19 | 348, 349P |
| Penstemon davidsonii | 21 | 126 |
| Penstemon davidsonii | 41 | 246 |
| Penstemon davidsonii | 45 | 212 |
| Penstemon davidsonii | 48 | 153 |
| Penstemon davidsonii | 52 | 156 |
| Penstemon davidsonii | 54 | 174, 180P |
| Penstemon davidsonii | 62 | 467 |
| Penstemon davidsonii | 66 | 107 |
| Penstemon davidsonii | 71 | 356 |
| Penstemon davidsonii subsp. davidsonii | 62 | 467 |
| Penstemon davidsonii subsp. menziesii | 61 | 464 |
| Penstemon davidsonii subsp. menziesii | 62 | 473C |
| Penstemon davidsonii subsp. praeteritus | 62 | 467 |
| Penstemon davidsonii subsp. praeteritus | 70 | 25C, 26 |
| Penstemon davidsonii roseus | 3 | 52 |
| Penstemon deamii | 62 | 159 |
| Penstemon degeneri | 62 | 162 |
| Penstemon desertipicti | 16 | 22 |
| Penstemon deustus | 7 | 202 |
| Penstemon deustus | 48 | 332 |
| Penstemon deustus | 62 | 164 |
| Penstemon deustus | 71 | 92 |
| Penstemon deustus | 78 | 406 |
| Penstemon deustus var. pedicellatus | 62 | 164 |
| Penstemon diffusus | 4 | 334 |
| Penstemon diffusus | 25 | 46 |
| Penstemon diffusus | 45 | 209 |
| Penstemon digitalis | 62 | 159, 474 |
| Penstemon digitalis 'Husker Red' | 62 | 472 |
| Penstemon dissectus | 18 | 34 |
| Penstemon dissectus | 62 | 180 |
| Penstemon distans | 62 | 170 |
| Penstemon dolius | 10 | 79 |
| Penstemon dolius | 12 | 67 |
| Penstemon dolius | 62 | 169 |
| Penstemon douglasii | 3 | 295 |
| Penstemon douglasii | 4 | 323 |
| Penstemon duchesnensis | 62 | 406 |
| Penstemon duchesnensis | 67 | 55 |
| Penstemon eatonii | 9 | 350 |
| Penstemon eatonii | 29 | R 21 |
| Penstemon eatonii | 62 | 175, 177 |
| Penstemon elegantulus | 62 | 162 |
| Penstemon ellipticus | 62 | 467 |
| Penstemon eriantherus | 2 | 9 |
| Penstemon eriantherus | 10 | 225, 227P |
| Penstemon eriantherus | 16 | 28 |
| Penstemon eriantherus | 29 | R 21 |
| Penstemon eriantherus | 41 | 254 |
| Penstemon eriantherus | 48 | 333 |
| Penstemon eriantherus | 51 | 339 |
| Penstemon eriantherus | 53 | 172, 177, 179 |
| Penstemon eriantherus | 60 | 274, 275C |
| Penstemon eriantherus | 62 | 168 |
| Penstemon eriantherus | 63 | 61 |
| Penstemon eriantherus | 64 | 81 |
| Penstemon eriantherus | 73 | 97C |
| Penstemon eriantherus | 80 | 77, 78C |
| Penstemon eriantherus var. argillosus | 62 | 169 |
| Penstemon eriantherus var. eriantherus | 62 | 169 |
| Penstemon eriantherus var. whitedii | 62 | 169 |
| Penstemon euglaucus | 62 | 161 |
| Penstemon eximeus | 62 | 177 |
| Penstemon fasciculatus | 62 | 175 |
| Penstemon Fate-Seeba hybrids | 62 | 472 |
| Penstemon fendleri | 62 | 176 |
| Penstemon filiformis | 62 | 180 |
| Penstemon filisepalis | 62 | 175 |
| Penstemon flavescens | 53 | 172 |
| Penstemon flavescens | 62 | 160, 161 |
| Penstemon floribundus | 62 | 178 |
| Penstemon floridus | 62 | 177 |
| Penstemon floridus | 66 | 94, 95C |
| Penstemon floridus var. augustinii | 62 | 177 |
| Penstemon flowersii | 62 | 176 |
| Penstemon fremontii | 62 | 172 |
| Penstemon fructiformis | 62 | 177 |
| Penstemon frutescens | 55 | 315 |
| Penstemon frutescens | 57 | 232-4 |
| Penstemon frutescens | 62 | 180 |
| Penstemon fruticosus | 4 | 323, 324 |
| Penstemon fruticosus | 7 | 202, 203P |
| Penstemon fruticosus | 10 | 42 |
| Penstemon fruticosus | 41 | 204 |
| Penstemon fruticosus | 49 | 174 |
| Penstemon fruticosus | 51 | 352 |
| Penstemon fruticosus | 53 | 179 |
| Penstemon fruticosus | 62 | 406, 467, 468C, 475 |
| Penstemon fruticosus | 65 | 252 |
| Penstemon gairdneri | 15 | 183 |
| Penstemon gairdneri | 23 | 355 |
| Penstemon gairdneri | 41 | 247 |
| Penstemon gairdneri | 58 | 236 |
| Penstemon gairdneri | 62 | 164 |
| Penstemon gairdneri subsp. hians | 62 | 164 |
| Penstemon 'Garnet' | 62 | 471 |
| Penstemon garrettii | 17 | 65 |
| Penstemon gentianoides | 62 | 175 |
| Penstemon 'George Home' | 74 | 29 |
| Penstemon gibbensii | 62 | 174 |
| Penstemon glaber | 4 | 326 |
| Penstemon glaber | 16 | 27 |
| Penstemon glaber | 23 | 14 |
| Penstemon glaber | 45 | 31 |
| Penstemon glaber | 48 | 336 |
| Penstemon glaber | 62 | 171 |
| Penstemon glaber alpinus | 4 | 326 |
| Penstemon glaber alpinus | 62 | 172 |
| Penstemon glaber var. brandegei | 62 | 172 |
| Penstemon glaber var. glaber | 62 | 172 |
| Penstemon glandulosus | 50 | 99P, 107 |
| Penstemon glandulosus | 62 | 180 |
| Penstemon glaucinus | 62 | 161 |
| Penstemon glaucus stenosepalus | 9 | 22 |
| Penstemon globosus | 52 | 155 |
| Penstemon globosus | 62 | 161 |
| Penstemon 'Gloxinioides' | 62 | 472 |
| Penstemon 'Goldie' | 62 | 472 |
| Penstemon goodrichii | 62 | 169 |
| Penstemon gordoni | 4 | 326 |
| Penstemon gordoni splendens | 4 | 326 |
| Penstemon gormannii | 62 | 169 |
| Penstemon gracilentis | 48 | 157 |
| Penstemon gracilentis | 62 | 180 |
| Penstemon gracilis | 62 | 159 |
| Penstemon grahamii | 62 | 169 |
| Penstemon grandiflorus | 62 | 176, 474, 475 |
| Penstemon 'Grape Tart' | 62 | 471 |
| Penstemon griffinii | 62 | 162 |
| Penstemon grinnellii | 62 | 177 |
| Penstemon grinnellii subsp. scorpularioides | 62 | 177 |
| Penstemon hallii | 9 | 22 |
| Penstemon hallii | 17 | 28 |
| Penstemon hallii | 29 | R 21 |
| Penstemon hallii | 49 | 67 |
| Penstemon hallii | 60 | 160, 162C, 164 |
| Penstemon hallii | 62 | 171 |
| Penstemon hallii | 70 | 69 |
| Penstemon harbouri | 18 | 347 |
| Penstemon harbouri | 62 | 163 |
| Penstemon harringtonii | 62 | 176 |
| Penstemon hartwegii | 4 | 333 |
| Penstemon hartwegii | 62 | 175 |
| Penstemon harvardii | 62 | 178 |
| Penstemon haydenii | 55 | 55 |
| Penstemon haydenii | 62 | 176, 177C |
| Penstemon hesperius | 62 | 161 |
| Penstemon heterodoxus | 41 | 203 |
| Penstemon heterodoxus | 49 | 69 |
| Penstemon heterodoxus | 54 | 320, 322 |
| Penstemon heterodoxus | 62 | 161 |
| Penstemon heterodoxus | 66 | 99 |
| Penstemon heterodoxus | 78 | 102C, 103 |
| Penstemon heterophyllus | 4 | 324 |
| Penstemon heterophyllus | 36 | 77 |
| Penstemon heterophyllus | 62 | 178 |
| Penstemon heterophyllus | 65 | 80 |
| Penstemon heterophyllus | 78 | 404C, 406 |
| Penstemon heterophyllus | 81 | 316 |
| Penstemon heterophyllus subsp. australis | 62 | 178 |
| Penstemon heterophyllus purdyi | 4 | 324 |
| Penstemon heterophyllus purdyi | 62 | 178, 406 |
| Penstemon heterophyllus 'True Blue' | 4 | 324 |
| Penstemon heterophyllus 'True Blue' | 16 | 60 |
| Penstemon heterophyllus 'True Blue' | 26 | 71 |
| Penstemon heterophyllus 'True Blue' | 30 | 297 |
| Penstemon heterophyllus 'True Blue' | 62 | 472 |
| Penstemon hirsutus | 4 | 326 |
| Penstemon hirsutus | 62 | 159 |
| Penstemon hirsutus var. minimus | 62 | 159 |
| Penstemon hirsutus var. pygmaeus | 62 | 159 |
| Penstemon hirsutus var. pygmaeus | 71 | 356 |
| Penstemon hirsutus 'Pygmaeus' | 46 | 285, 310P |
| Penstemon hirsutus 'Pygmaeus' | 54 | 174 |
| Penstemon hirsutus 'Pygmaeus' | 56 | 136 |
| Penstemon hirsutus 'Pygmaeus' | 61 | 464 |
| Penstemon humilis | 4 | 74 |
| Penstemon humilis | 9 | 12 |
| Penstemon humilis | 16 | 22 |
| Penstemon humilis | 18 | 380 |
| Penstemon humilis | 53 | 247 |
| Penstemon humilis | 62 | 161 |
| Penstemon humilis var. brevifolius | 41 | 252 |
| Penstemon hybrids | 62 | 471 |
| Penstemon imberis | 62 | 175 |
| Penstemon immanifestus | 62 | 176 |
| Penstemon incertus | 62 | 177 |
| Penstemon isophyllus | 4 | 330 |
| Penstemon isophyllus | 62 | 175 |
| Penstemon jaffrayanus | 4 | 325 |
| Penstemon jamesii | 62 | 169 |
| Penstemon jamesii brevicaulus | 12 | 71 |
| Penstemon janishiae | 58 | 253, 255 |
| Penstemon janishiae | 62 | 169 |
| Penstemon janishiae | 67 | 52 |
| Penstemon janishiae | 71 | 66 |
| Penstemon x johnsoniae | 62 | 174 |
| Penstemon x jonesii | 62 | 174 |
| Penstemon kerryi | 48 | 336 |
| Penstemon kingii | 10 | 79 |
| Penstemon kingii | 62 | 178 |
| Penstemon kunthii | 58 | 189 |
| Penstemon kunthii | 62 | 175 |
| Penstemon labrosus | 4 | 333 |
| Penstemon labrosus | 10 | 79 |
| Penstemon labrosus | 62 | 175 |
| Penstemon laetus | 4 | 325 |
| Penstemon laetus | 62 | 178 |
| Penstemon laetus var. roezlii | 62 | 178 |
| Penstemon laevigatus | 62 | 159 |
| Penstemon laevis | 62 | 174 |
| Penstemon lanceolatus | 62 | 180 |
| Penstemon laricifolius | 10 | 218P, 225 |
| Penstemon laricifolius | 15 | 27 |
| Penstemon laricifolius | 16 | 15, 27 |
| Penstemon laricifolius | 23 | 355 |
| Penstemon laricifolius | 29 | R 21 |
| Penstemon laricifolius | 45 | 31 |
| Penstemon laricifolius | 48 | 333 |
| Penstemon laricifolius | 61 | 464 |
| Penstemon laricifolius | 62 | 164 |
| Penstemon laricifolius albus | 48 | 337 |
| Penstemon laricifolius var. exilifolius | 60 | 278 |
| Penstemon laricifolius var. exilifolius | 61 | 464 |
| Penstemon laricifolius var. exilifolius | 62 | 163C, 164 |
| Penstemon laricifolius var. laricifolius | 60 | 276 |
| Penstemon laxiflorus | 62 | 159 |
| Penstemon leiophyllus subsp. franciscipennellii | 62 | 172 |
| Penstemon leiophyllus subsp. franciscipennellii | 71 | 66 |
| Penstemon lentus | 62 | 176 |
| Penstemon leonardii | 15 | 184 |
| Penstemon leonardii | 62 | 178 |
| Penstemon leonardii var. higginsii | 62 | 178 |
| Penstemon leonardii var. leonardii | 62 | 178 |
| Penstemon leonardii var. patricus | 62 | 178 |
| Penstemon linarioides | 4 | 198, 329 |
| Penstemon linarioides | 69 | 157 |
| Penstemon linarioides subsp. californicus | 62 | 166 |
| Penstemon linarioides var. coloradense | 74 | 27, 28C |
| Penstemon linarioides subsp. coloradensis | 28 | 159 |
| Penstemon linarioides subsp. coloradensis | 62 | 166 |
| Penstemon linarioides subsp. coloradensis | 70 | 26 |
| Penstemon linarioides subsp. compactifolius | 62 | 166 |
| Penstemon linarioides subsp. linarioides | 62 | 166 |
| Penstemon linarioides subsp. linarioides var. sileri | 62 | 166 |
| Penstemon lyallii | 2 | 9 |
| Penstemon lyallii | 3 | 52 |
| Penstemon lyallii | 4 | 323 |
| Penstemon lyallii | 25 | 39 |
| Penstemon lyallii | 37 | 196 |
| Penstemon lyallii | 51 | 353 |
| Penstemon lyallii | 62 | 465 |
| Penstemon magnus | 62 | 174 |
| Penstemon marcusii | 62 | 169 |
| Penstemon mensarum | 62 | 172 |
| Penstemon menziesii | 2 | 9, 135, 366 |
| Penstemon menziesii | 3 | 295 |
| Penstemon menziesii | 4 | 323, 334 |
| Penstemon menziesii | 10 | 42 |
| Penstemon menziesii | 11 | 237 |
| Penstemon menziesii | 15 | 251 |
| Penstemon menziesii | 20 | 115, 309 |
| Penstemon menziesii | 24 | 37 |
| Penstemon menziesii | 25 | 45 |
| Penstemon menziesii | 48 | 26 |
| Penstemon menziesii | 54 | 270, 320 |
| Penstemon menziesii davidsonii | 5 | 19A.M. |
| Penstemon menziesii davidsonii | 10 | 45 |
| Penstemon menziesii davidsonii | 62 | 58 |
| Penstemon menziesii subsp. microphyllus | 23 | 56 |
| Penstemon menziesii subsp. microphyllus | 59 | 309, 310C |
| Penstemon menziesii 'Microphyllus' | 54 | 174 |
| Penstemon menziesii robinsonii | 4 | 330 |
| Penstemon micranthus | 4 | 325 |
| Penstemon militaris | 62 | 160 |
| Penstemon miser | 15 | 180 |
| Penstemon miser | 58 | 255 |
| Penstemon miser | 62 | 170 |
| Penstemon moffatii | 62 | 169 |
| Penstemon moffatii subsp. paysonii | 62 | 169 |
| Penstemon monoensis | 62 | 170 |
| Penstemon montanus | 15 | 30 |
| Penstemon montanus | 27 | 213 |
| Penstemon montanus | 29 | R 21 |
| Penstemon montanus | 53 | 247 |
| Penstemon montanus | 62 | 406, 469 |
| Penstemon montanus var. idahoensis | 62 | 469 |
| Penstemon montanus var. montanus | 62 | 469 |
| Penstemon multicaulis | 62 | 159 |
| Penstemon multiflorus | 62 | 162 |
| Penstemon murrayanus | 62 | 475 |
| Penstemon nanus | 62 | 169 |
| Penstemon nelsonae | 22 | 151 |
| Penstemon nemorosus | 15 | 249 |
| Penstemon nemorosus | 58 | 236 |
| Penstemon nemorosus | 62 | 180 |
| Penstemon neomexicanus | 62 | 174 |
| Penstemon neotericus | 62 | 180 |
| Penstemon newberryi | 2 | 366 |
| Penstemon newberryi | 4 | 325, 331P |
| Penstemon newberryi | 17 | 359 |
| Penstemon newberryi | 21 | 126 |
| Penstemon newberryi | 23 | 56 |
| Penstemon newberryi | 25 | 176 |
| Penstemon newberryi | 33 | 226 |
| Penstemon newberryi | 48 | 153 |
| Penstemon newberryi | 55 | 210* |
| Penstemon newberryi | 56 | 135 |
| Penstemon newberryi | 58 | 189, 203C, 204C |
| Penstemon newberryi | 60 | 335 |
| Penstemon newberryi | 62 | 465, 466C, 469 |
| Penstemon newberryi | 66 | 106, 107 |
| Penstemon newberryi | 73 | 22 |
| Penstemon newberryi | 75 | 149C |
| Penstemon newberryi | 78 | 406 |
| Penstemon newberryi rupicola | 4 | 330 |
| Penstemon newberryi rupicola | 10 | 45 |
| Penstemon newberryi rupicola | 11 | 237 |
| Penstemon nitidus | 37 | 380 |
| Penstemon nitidus | 62 | 175 |
| Penstemon nitidus | 65 | 428-429P.C. |
| Penstemon nudiflorus | 62 | 172 |
| Penstemon oklahomensis | 15 | 24 |
| Penstemon oklahomensis | 62 | 159 |
| Penstemon oliganthus | 6 | 115 |
| Penstemon oliganthus | 19 | 46 |
| Penstemon oliganthus | 62 | 162 |
| Penstemon ophianthus | 62 | 169 |
| Penstemon ophianthus | 71 | 66 |
| Penstemon oreocharis | 62 | 161 |
| Penstemon osterhoutii | 62 | 176 |
| Penstemon ovatus | 4 | 326 |
| Penstemon ovatus | 20 | 115 |
| Penstemon ovatus | 62 | 162 |
| Penstemon pachyphyllus | 62 | 175 |
| Penstemon pachyphyllus var. mucronatus | 62 | 175 |
| Penstemon pallidus | 62 | 159 |
| Penstemon palmeri | 23 | 296 |
| Penstemon palmeri | 27 | 209 |
| Penstemon palmeri | 29 | R 21 |
| Penstemon palmeri | 53 | 250 |
| Penstemon palmeri | 61 | 370 |
| Penstemon palmeri | 62 | 177, 179C, 475 |
| Penstemon palmeri subsp. eglandulosus | 62 | 177 |
| Penstemon palmeri subsp. palmeri | 62 | 177 |
| Penstemon parryi | 62 | 177 |
| Penstemon parviflorus | 62 | 170 |
| Penstemon parvulus | 62 | 180 |
| Penstemon parvus | 62 | 174 |
| Penstemon patens | 66 | 94 |
| Penstemon payettensis | 53 | 250 |
| Penstemon payettensis | 62 | 172C |
| Penstemon paysoniorum | 62 | 172 |
| Penstemon peckii | 62 | 160 |
| Penstemon penlandii | 62 | 174 |
| Penstemon pennellianus | 41 | 248 |
| Penstemon pennellianus | 62 | 172 |
| Penstemon perfoliatus | 62 | 175 |
| Penstemon perpulcher | 62 | 172 |
| Penstemon petiolatus | 10 | 22 |
| Penstemon petiolatus | 62 | 178 |
| Penstemon pinifolius | 12 | 72 |
| Penstemon pinifolius | 15 | 184 |
| Penstemon pinifolius | 19 | 71 |
| Penstemon pinifolius | 23 | 355 |
| Penstemon pinifolius | 25 | 170, 306 |
| Penstemon pinifolius | 26 | 220 |
| Penstemon pinifolius | 27 | 140 |
| Penstemon pinifolius | 29 | R 18 |
| Penstemon pinifolius | 30 | 31 |
| Penstemon pinifolius | 32 | 61, 150 |
| Penstemon pinifolius | 36 | 78 |
| Penstemon pinifolius | 39 | 42 |
| Penstemon pinifolius | 41 | 131 |
| Penstemon pinifolius | 48 | 26 |
| Penstemon pinifolius | 54 | 181 |
| Penstemon pinifolius | 55 | 262, 263 |
| Penstemon pinifolius | 56 | 195* |
| Penstemon pinifolius | 61 | 464 |
| Penstemon pinifolius | 62 | 174 |
| Penstemon pinifolius | 66 | 180 |
| Penstemon pinifolius 'Mersea Yellow' | 55 | 331P, 346A.M.* |
| Penstemon pinifolius 'Mersea Yellow' | 57 | 92 |
| Penstemon pinifolius 'Mersea Yellow' | 61 | 464 |
| Penstemon pinifolius 'Wisley Flame' | 71 | 253 |
| Penstemon 'Pink Dust' | 62 | 471 |
| Penstemon 'Pink Holly' | 62 | 471 |
| Penstemon platyphyllus | 62 | 180 |
| Penstemon 'Prairie Dawn' | 62 | 471 |
| Penstemon 'Prairie Dusk' | 62 | 471 |
| Penstemon 'Prairie Fire' | 62 | 471 |
| Penstemon 'Prairie Pink' | 62 | 471 |
| Penstemon pratensis | 62 | 160 |
| Penstemon pringlei | 62 | 170 |
| Penstemon procerus | 4 | 325, 334 |
| Penstemon procerus | 6 | 119 |
| Penstemon procerus | 7 | 201 |
| Penstemon procerus | 45 | 212 |
| Penstemon procerus | 49 | 67 |
| Penstemon procerus | 51 | 347 |
| Penstemon procerus | 52 | 153, 154, 155 |
| Penstemon procerus | 53 | 249 |
| Penstemon procerus | 54 | 318, 320 |
| Penstemon procerus | 58 | 236 |
| Penstemon procerus | 59 | 307 |
| Penstemon procerus | 62 | 160 |
| Penstemon procerus | 78 | 405C |
| Penstemon procerus 'Roy Davidson' | 81 | 316 |
| Penstemon procerus subsp. aberrans | 62 | 161 |
| Penstemon procerus 'Alba' | 62 | 472 |
| Penstemon procerus subsp. brachyanthus | 62 | 161 |
| Penstemon procerus subsp. formosus | 62 | 161, 406 |
| Penstemon procerus micranthus | 4 | 325 |
| Penstemon procerus subsp. modestus | 62 | 161 |
| Penstemon procerus 'Nisqually Cream' | 62 | 472 |
| Penstemon procerus tolmiei | 4 | 198 |
| Penstemon procerus tolmiei | 60 | 335 |
| Penstemon procerus tolmiei | 62 | 160, 406 |
| Penstemon procerus tolmiei | 64 | 103 |
| Penstemon procerus tolmiei | 66 | 180 |
| Penstemon procerus 'True Blue' | 62 | 472 |
| Penstemon pruinosus | 62 | 162 |
| Penstemon pseudospectabilis | 62 | 177 |
| Penstemon pubescens | 4 | 326 |
| Penstemon pulchellus | 20 | 115 |
| Penstemon pumilus | 16 | 23 |
| Penstemon pumilus | 60 | 378 |
| Penstemon pumilus | 62 | 169, 170C |
| Penstemon pumilus | 67 | 58 |
| Penstemon punctatus | 62 | 170 |
| Penstemon purpusii | 41 | 254 |
| Penstemon purpusii | 62 | 178 |
| Penstemon radicosus | 62 | 162 |
| Penstemon ramaleyi | 62 | 166 |
| Penstemon rattanii | 15 | 187 |
| Penstemon rattanii | 62 | 162 |
| Penstemon repens | 16 | 60 |
| Penstemon richardsonii | 4 | 333 |
| Penstemon richardsonii | 48 | 156 |
| Penstemon richardsonii | 62 | 180 |
| Penstemon roezlii | 2 | 9 |
| Penstemon roezlii | 3 | 52 |
| Penstemon roezlii | 4 | 325 |
| Penstemon roezlii | 60 | 335 |
| Penstemon roezlii, (true) | 16 | 237 |
| Penstemon 'Rose Elf' | 62 | 471 |
| Penstemon rostriflorus | 62 | 175, 475 |
| Penstemon rostriflorus | 66 | 94, 95C, 98 |
| Penstemon rubicundus | 29 | R 21 |
| Penstemon rubicundus | 62 | 177 |
| Penstemon rupicola | 2 | 9, 366 |
| Penstemon rupicola | 3 | 295 |
| Penstemon rupicola | 4 | 329 |
| Penstemon rupicola | 10 | 42 |
| Penstemon rupicola | 11 | 237 |
| Penstemon rupicola | 15 | 174 |
| Penstemon rupicola | 18 | 264 |
| Penstemon rupicola | 28 | 27 |
| Penstemon rupicola | 39 | 45 |
| Penstemon rupicola | 41 | 247 |
| Penstemon rupicola | 43 | 260 |
| Penstemon rupicola | 45 | 211 |
| Penstemon rupicola | 48 | 154 |
| Penstemon rupicola | 51 | 350 |
| Penstemon rupicola | 54 | 174 |
| Penstemon rupicola | 60 | 335 |
| Penstemon rupicola | 62 | 58, 406, 468C, 469 |
| Penstemon rupicola | 64 | 103 |
| Penstemon rupicola 'Alba' | 62 | 472 |
| Penstemon rupicola 'Diamond Lake' | 62 | 472 |
| Penstemon rydbergii | 6 | 119 |
| Penstemon rydbergii | 7 | 202 |
| Penstemon rydbergii | 48 | 338 |
| Penstemon rydbergii | 53 | 177 |
| Penstemon rydbergii | 62 | 160 |
| Penstemon saxosorum | 62 | 174 |
| Penstemon scapoides | 62 | 180 |
| Penstemon scapoides | 66 | 96 |
| Penstemon scariosus | 62 | 172 |
| Penstemon scariosus var. albifluvis | 62 | 172 |
| Penstemon scariosus var. cyanomontanus | 62 | 172 |
| Penstemon scariosus var. garrettii | 62 | 172 |
| Penstemon scariosus var. scariosus | 62 | 172 |
| Penstemon scouleri | 19 | 378A.M. |
| Penstemon scouleri | 62 | 467 |
| Penstemon scouleri | 2 | 9, 366 |
| Penstemon scouleri | 3 | 52 |
| Penstemon scouleri | 4 | 323, 327P, 328P, 334 |
| Penstemon scouleri | 10 | 42 |
| Penstemon scouleri | 11 | 237 |
| Penstemon scouleri | 16 | 60 |
| Penstemon scouleri | 20 | 115 |
| Penstemon scouleri | 23 | 14, 56 |
| Penstemon scouleri | 27 | 367 |
| Penstemon scouleri | 30 | 32 |
| Penstemon scouleri | 31 | 352 |
| Penstemon scouleri albus | 4 | 323, 327P, 328P |
| Penstemon scouleri albus | 47 | 40, 43P, 163 |
| Penstemon scouleri albus | 54 | 174 |
| Penstemon scouleri albus | 70 | 145 |
| Penstemon scouleri 'Albus' | 74 | 27, 28C |
| Penstemon scouleri x rupicola | 62 | 467 |
| Penstemon scouleri var. scouleri 'Alba' | 62 | 472 |
| Penstemon scouleri var. scouleri 'Charming' | 62 | 472 |
| Penstemon scouleri var. serratus | 62 | 467 |
| Penstemon Section Bacharifolii | 62 | 180 |
| Penstemon Section Coerulei | 62 | 175 |
| Penstemon Section Cristati | 62 | 168 |
| Penstemon Section Dasanthera | 62 | 465 |
| Penstemon Section Dentanthera | 62 | 180 |
| Penstemon Section Elmigera | 62 | 174 |
| Penstemon Section Ericopsis | 62 | 164 |
| Penstemon Section Fasciculus | 62 | 175 |
| Penstemon Section Habroanthus | 62 | 171 |
| Penstemon Section hybrid colonies | 62 | 470 |
| Penstemon Section identification | 62 | 469 |
| Penstemon Section Peltanthera | 62 | 176 |
| Penstemon Section Penstemon | 62 | 159 |
| Penstemon Section Saccanthera | 62 | 178 |
| Penstemon Section Subsection Arenarii | 62 | 164 |
| Penstemon Section Subsection Centranthifolii | 62 | 177 |
| Penstemon Section Subsection Deusti | 62 | 164 |
| Penstemon Section Subsection Gairdneriani | 62 | 164 |
| Penstemon Section Subsection Graciles | 62 | 159 |
| Penstemon Section Subsection Harbouriana | 62 | 163 |
| Penstemon Section Subsection Harvardii | 62 | 178 |
| Penstemon Section Subsection Humiles | 62 | 161 |
| Penstemon Section Subsection Multiflori | 62 | 163 |
| Penstemon Section Subsection Petiolati | 62 | 178 |
| Penstemon Section Subsection Proceri | 62 | 159 |
| Penstemon Section Subsection Serrulati | 62 | 180 |
| Penstemon Section Subsection Spectabilis | 62 | 177 |
| Penstemon Section Subsection Tubaeflori | 62 | 163 |
| Penstemon secundiflorus | 29 | R 21 |
| Penstemon secundiflorus | 48 | 338 |
| Penstemon secundiflorus | 60 | 278 |
| Penstemon secundiflorus | 62 | 175 |
| Penstemon serrulatus | 15 | 251 |
| Penstemon serrulatus | 58 | 189 |
| Penstemon serrulatus | 62 | 180 |
| Penstemon serrulatus | 73 | 28 |
| Penstemon serrulatus | 78 | 407 |
| Penstemon shastensis | 62 | 161 |
| Penstemon 'Six Hills' | 20 | 137 |
| Penstemon 'Six Hills' | 23 | 56 |
| Penstemon 'Six Hills' | 31 | 352 |
| Penstemon 'Six Hills' | 62 | 472 |
| Penstemon 'Six Hills' | 65 | 238C |
| Penstemon smallii | 4 | 326 |
| Penstemon smallii | 62 | 159 |
| Penstemon sp. (Idaho) | 16 | 23 |
| Penstemon sp. (Idaho) | 25 | 100 |
| Penstemon sp. nov. (New Mexico) | 19 | 46 |
| Penstemon spathulatus | 62 | 161 |
| Penstemon speciosus | 48 | 153 |
| Penstemon speciosus | 52 | 149 |
| Penstemon speciosus | 54 | 313C, 320, 328 |
| Penstemon speciosus | 62 | 171C, 172, 174 |
| Penstemon speciosus | 66 | 99 |
| Penstemon speciosus subsp. kennedyi | 61 | 466 |
| Penstemon speciosus subsp. kennedyi | 62 | 172 |
| Penstemon speciosus subsp. lemhiensis | 62 | 172 |
| Penstemon spectabilis | 62 | 177 |
| Penstemon spp. list of, for rock gardens | 18 | 289 |
| Penstemon stenophyllus | 62 | 180 |
| Penstemon stenosepalus | 4 | 329 |
| Penstemon strictiformis | 62 | 172 |
| Penstemon strictus | 62 | 172 |
| Penstemon subglaber | 27 | 211, 213 |
| Penstemon subglaber | 29 | R 21 |
| Penstemon subglaber | 62 | 172 |
| Penstemon subserratus | 62 | 162 |
| Penstemon subulatus | 62 | 177 |
| Penstemon sudans | 12 | 72 |
| Penstemon suffrutescens | 9 | 350 |
| Penstemon suffrutescens | 16 | 22 |
| Penstemon tenuiflorus | 62 | 159 |
| Penstemon tenuifolius | 62 | 175 |
| Penstemon teucrioides | 6 | 114P, 115 |
| Penstemon teucrioides | 19 | 38 |
| Penstemon teucrioides | 38 | 273 |
| Penstemon teucrioides | 62 | 166, 167C |
| Penstemon thompsonae | 10 | 23 |
| Penstemon thompsonae | 62 | 166 |
| Penstemon thompsonae | 69 | 540P.C., 541C |
| Penstemon thompsoniae var. desperatus | 62 | 166 |
| Penstemon thurberi | 62 | 166 |
| Penstemon tidestromii | 27 | 209 |
| Penstemon tidestromii | 62 | 174 |
| Penstemon tolmei | 15 | 249 |
| Penstemon torryi | 4 | 333 |
| Penstemon traceyi | 62 | 164 |
| Penstemon triflorus | 62 | 170 |
| Penstemon triphyllus | 45 | 24 |
| Penstemon triphyllus | 62 | 180 |
| Penstemon triphyllus subsp. diphyllus | 62 | 180, 475 |
| Penstemon tristis | 16 | 23 |
| Penstemon tubaeflorus | 62 | 163 |
| Penstemon tusharensis | 62 | 165 |
| Penstemon tweedyi | 62 | 162 |
| Penstemon uintahensis | 62 | 172 |
| Penstemon uintahensis A.M. | JR-3 | 24C |
| Penstemon uintahensis P.C. | JR-1 | 53 |
| Penstemon unilateralis | 17 | 28 |
| Penstemon unilateralis | 20 | 123 |
| Penstemon unilateralis | 29 | R 21 |
| Penstemon utahensis | 62 | 177 |
| Penstemon variabilis | 62 | 164 |
| Penstemon vaseyanus | 62 | 161 |
| Penstemon venustus | 23 | 131 |
| Penstemon venustus | 25 | 100 |
| Penstemon venustus | 52 | 149 |
| Penstemon venustus | 62 | 180 |
| Penstemon versicolor | 16 | 15, 35P |
| Penstemon virens | 49 | 64 |
| Penstemon virens | 50 | 304P, 305A.M.* |
| Penstemon virens | 60 | 146, 274 |
| Penstemon virens | 62 | 162C |
| Penstemon virgatus | 62 | 172 |
| Penstemon virgatus subsp. arizonicus | 62 | 172 |
| Penstemon virgatus subsp. arizonicus | 63 | 93 |
| Penstemon virgatus subsp. asagrayi | 62 | 172 |
| Penstemon virgatus subsp. putus | 62 | 172 |
| Penstemon virgatus subsp. virgatus | 62 | 172 |
| Penstemon wardii | 62 | 174 |
| Penstemon washingtonensis | 62 | 161 |
| Penstemon watsonii | 62 | 160 |
| Penstemon 'Waxworks' | 62 | 471 |
| Penstemon wherryi | 62 | 159 |
| Penstemon whippleanus | 4 | 329 |
| Penstemon whippleanus | 9 | 22 |
| Penstemon whippleanus | 10 | 79 |
| Penstemon whippleanus | 15 | 22 |
| Penstemon whippleanus | 17 | 28 |
| Penstemon whippleanus | 50 | 105P, 108, 288 |
| Penstemon whippleanus | 60 | 146 |
| Penstemon whippleanus | 62 | 162 |
| Penstemon whippleanus | 76 | 445C |
| Penstemon 'White Knight' | 62 | 471 |
| Penstemon wilcoxii | 62 | 162 |
| Penstemon 'Will Ingwersen' | 62 | 471 |
| Penstemon wislizenii | 62 | 175 |
| Penstemon wrightii | 62 | 177 |
| Penstemon xylis | 62 | 166 |
| Penstemon yampaensis | 62 | 165C, 166 |