| Penstemon 'Evelyn' |
|
| Penstemon 'Garnet' |
Penstemon heterophyllus Lindl. |
| Penstemon 'Red Riding Hood' |
Penstemon hirsutus (L.) Willd. |
| Penstemon albertinus Greene |
Penstemon hirsutus (L.) Willd. 'Albiflorus' |
| Penstemon alpinus Torr. |
Penstemon hirsutus (L.) Willd. 'Pygmaeus' |
| Penstemon arkansanus Pennell |
Penstemon humilis Nutt. ex A. Gray. |
| Penstemon attennuatus Douglas ex Lindley ssp. attenuatus |
Penstemon janishiae N. Holmgren |
| Penstemon auriberbis Pennell |
Penstemon kunthii G. Don. |
| Penstemon azureus Benth. |
Penstemon laevigatus Aiton |
| Penstemon barbatus (Cavanilles) Rothrock |
Penstemon linarioides Gray ssp. coloradoensis (A. Nelson) Keck |
| Penstemon barbatus (Cavanilles) Rothrock 'Praecox Nanus' |
|
| Penstemon barrettiae Gray |
Penstemon lyallii A.Gray |
| Penstemon buckleyi Pennell |
Penstemon mensarum Pennell |
| Penstemon caeruleus Nutt. 'Schonholzeri' |
Penstemon neomexicanus Wooten & Standley |
| Penstemon caespitosus Nutt. ex A. Gray. |
Penstemon neotericus Keck |
| Penstemon campanulatus Willd. |
Penstemon newberryi A. Gray. |
| Penstemon cardwellii T.J. Howell. |
Penstemon palmeri A. Gray var. eglandulosus (Keck) N. Holmgren |
| Penstemon centranthifolius (Benth.) Benth. |
Penstemon parvulus (Gray) Krautt. |
| Penstemon cinicola Keck |
Penstemon pennellianus Keck |
| Penstemon confertus Douglas ex Lindley |
Penstemon pinifolius Greene |
| Penstemon davidsonii Greene |
Penstemon pinifolius Greene 'Mersea Yellow' |
| Penstemon davidsonii Greene var. menziesii (D.D.Keck) Cronquist |
Penstemon procerus Douglas ex Graham var brachyanthus (Pennell) Cronquist |
| Penstemon davidsonii Greene var. menziesii-prostata (D.D.Keck) Cronquist |
Penstemon procerus Douglas ex Graham var procerus |
| Penstemon deustus Douglas |
Penstemon procerus Douglas ex Graham var tolmiei (Hooker) Cronquist |
| Penstemon digitalis Nutt. ex Sims |
Penstemon pruinosus Douglas ex Lindl. |
| Penstemon discolor Keck |
Penstemon purpusii Brand. |
| Penstemon dolius M.E.Jones var. duchesnensis N. Holmgren |
Penstemon richardsonii Douglas. |
| Penstemon eatonii A. Gray ssp. undosus (M.E. Jones) Keck |
Penstemon rostriflorus Kellogg. |
| Penstemon eriantherus Pursh. |
Penstemon rupicola (Piper) Howell. |
| Penstemon euglaucus English. |
Penstemon rupicola (Piper) Howell. 'Alba' |
| Penstemon floridus Brandeg. var. austinii (Eastw.) N. Holmgren |
Penstemon rupicola (Piper) Howell. 'Karol' |
| Penstemon fruticosus Greene |
Penstemon rydbergii A.Nelson var. oreocharis (Greene) N. Holmgren |
| Penstemon fruticosus Greene var. scouleri (Lindley) Cronquist |
Penstemon serrulatus Menz. |
| Penstemon glaber Pursh var alpinus (Torr.) A.Gray |
Penstemon venustus Douglas ex Lindley |
| Penstemon gormanii Greene |
Penstemon virgatus Gray. ssp. arizonicus (A.Gray) D.D.Keck |
| Penstemon grinnellii Eastw. var. scrophularioides (M.E. Jones) N.H. Holmgren |
Penstemon whippleanus Gray. |
| Penstemon hallii A. Gray. |
|
| Penstemon hartwegii Benth. |
|
