| Taxon | Collector | Location | Type Status | Barcode | |
|---|---|---|---|---|---|
| Penstemon isophyllus B.L.Rob. | C. A. Purpus 3276 Jul 1908 | Mexico. Cerro Verde, Oaxaca. | 773104 |  | |
| Penstemon isophyllus B.L.Rob. | H. E. Seaton 172 05 Aug 1891 | Mexico. Mt. Orizaba. | 773114 |  | |
| Penstemon isophyllus B.L.Rob. | H. H. Iltis 1142 with Robert Koeppen Frank Iltis, 20 Aug 1960 | Mexico. Oaxaca. Terribly eroded and overgrazed slope below Pan-Am. Highway at Puerto Herrera (km 420), just nortwest of Vanhuitlan. | 773109 |  | |
| Penstemon isophyllus B.L.Rob. | F. Ventura A. 2111 15 Aug 1970 | Mexico. Puebla. Ciudad Serdán. | 773115 |  | |
| Penstemon isophyllus B.L.Rob. | L. W. Lenz 18708 27 Nov 1953 | United States of America. California. Rancho Santa Ana Botanic Garden. | 773107 |  | |
| Penstemon isophyllus B.L.Rob. | L. W. Lenz 18708 27 Nov 1953 | United States of America. California. Rancho Santa Ana Botanic Garden. | 773106 |  | |
| Penstemon isophyllus B.L.Rob. | L. W. Lenz 18708 27 Nov 1953 | United States of America. California. Rancho Santa Ana Botanic Garden. | 773108 |  | |
| Penstemon isophyllus B.L.Rob. | E. K. Balls B5426 07 Aug 1938 | Mexico. Veracruz. Los Molinos, Perote. | 773116 |  | |
| Penstemon isophyllus B.L.Rob. | E. Lehto L21998 with D. J. Pinkava, B. Parfitt & T. Reeves, 02 Aug 1977 | Mexico. Veracruz. Mex 150-D, 0.4 mile east of Puebla-Vera Cruz state line. | 773118 |  | |
| Penstemon isophyllus B.L.Rob. | C. G. Pringle 8568 13 Aug 1901 | Mexico. Puebla. Above Chalchicomula. | isotype | 130573 |  |
| Penstemon isophyllus B.L.Rob. | D. E. Breedlove 26743 01 Aug 1972 | Mexico. Oaxaca. 13 km north of Telixtlahuaca along road to Cuicatlán. | 773101 |  | |
| Penstemon isophyllus B.L.Rob. | D. E. Breedlove 69621 26 Aug 1988 | Mexico. Oaxaca. 52 km west of Tlaxiaco on road to Putla. | 773102 |  | |
| Penstemon isophyllus B.L.Rob. | R. M. Straw 1041 with David P. Gregory, 25 Jul 1957 | Mexico. Oaxaca. Ca. 11 miles south of Nochixtlan on Mex. Highway 190. | 773110 |  | |
| Penstemon isophyllus B.L.Rob. | E. K. Balls B5426 with W. B. Gourlay, 07 Sep 1938 | Mexico. Los Molinos, Perote, Ver. | 773111 |  | |
| Penstemon isophyllus B.L.Rob. | E. K. Balls B5398 with W. B. Gourlay, 31 Aug 1938 | Mexico. Los Chinos, San Manuel de la Sierra, Sierra Negra, Pue. | 773112 |  | |
| Penstemon isophyllus B.L.Rob. | C. E. Smith, Jr. 5038 with Susan Kitchen, 05 Aug 1970 | Mexico. Nochixtlan Valley. Next to cattle yard near Llano Verde. | 773113 |  | |
| Penstemon isophyllus B.L.Rob. | J. I. Calzada 2485 with F. Lozano, 22 Jun 1976 | Mexico. Veracruz. En el Mal Pais, Carreieba Papa Tepeyahualco, Totalco. | 773117 |  | |
| Penstemon isophyllus B.L.Rob. | C. G. Alm 83 26 Sep 1947 | Mexico. Horto Botanico Upsaliensi Cultae. | 773105 |  | |
| Penstemon isophyllus B.L.Rob. | W. H. Camp 2687 19 Feb 1937-27 Feb 1937 | Mexico. Oaxaca. Zempoaltepetl: Middle slopes. | 773103 |  |