Flower color variation in Jones’ penstemon, Penstemon × jonesii Pennell (P. eatonii A. Gray × P. laevis Pennell) (Plantaginaceae)

Authors

W. Wesley Crump, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow
Jason M. Stettler, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow
Robert L. Johnson, Department of Biology, Brigham Young University, Provo, UT 84602; Monte L. Bean Museum, Brigham Young University, Provo, UT 84602Follow
Chris D. Anderson, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow
Sarah Harrison, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow
Lindsey M. Meservey, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow
Mikel R. Stevens, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602Follow

Abstract

Penstemon × jonesii is described as having flowers with the colors of “Tyrian rose,” “amaranth purple,” or “red-purple to maroon.” It has been recorded only in localized areas of southwestern Utah and just over the border of Arizona, where both putative parents commonly occur in sandy soils. Penstemon × jonesii has been reported and widely accepted as a natural hybrid of P. laevis × P. eatonii, though no research has been conducted to verify this assumption. We examined claims of its hybrid origin by making interspecific reciprocal first-generation hybrid plants from the 2 suspected parental species (P. eatonii and P. laevis) as well as by making second-generation hybrids through backcrossing to both parental species. Using 9 Penstemon simple sequence repeat (SSR), or microsatellite, markers, we examined the allelic variation among natural populations of P. × jonesii, P. eatonii, and P. laevis in southwestern Utah. These SSR data, in conjunction with our controlled crosses, support claims that P. × jonesii likely descends from hybridization events between P. eatonii and P. laevis. Flower color of the typical P. × jonesii reported in the literature and found in herbarium samples does not resemble the flower color of F₁ P. eatonii × P. laevis hybrids from our controlled crosses. However, in subsequent controlled backcrossing of the F₁ hybrids to P. eatonii, we found blossom morphotypes and corolla colors matching previous descriptions of P. × jonesii. We also observed many hybrids with lighter corolla colors, such as light pinks, pinkish yellows, and lavender, which are not recorded in the literature or found in herbarium specimens. Field surveys for natural color variation in P. × jonesii populations also revealed greater flower color variation than previously reported, which should be considered as part of this hybrid taxa as well, though the predominant floral colors of P. × jonesii are “Tyrian rose,” “amaranth purple,” and “red-purple to maroon,” which suggests some selective bias. We suggest that pollinator preference for dark red to purple blooms may be responsible for this phenomenon.


La planta Penstemon × jonesii, caracterizada por sus flores color “rosa de Tyria”, “violeta amaranto” o “rojo avioletado a rojo oscuro”. Ha sido registrada, únicamente, en determinadas áreas del suroeste de Utah y en suelos arenosos de la frontera de Arizona, donde es posible encontrar a sus presuntas especies parentales. Penstemon × jonesii ha sido documentada y ampliamente aceptada como un híbrido natural de P. laevis × P. eatonii. Sin embargo, no se han llevado a cabo investigaciones que verifiquen tal aseveración. Con el fin de, confirmar su origen híbrido cultivamos plantas híbridas recíprocas interespecíficas de primera generación de las dos supuestas especies parentales (P. eatonii y P. laevis), e híbridos de segunda generación, a través del retrocruzamiento de ambas especies parentales. Utilizando nueve marcadores de secuencia repetida simple (SSR, por sus siglas en inglés) o microsatélites, examinamos la variación alélica entre las poblaciones naturales de P. × jonesii, P. eatonii y P. laevis al suroeste de Utah. Estos datos de SSRs, junto con nuestros resultados de cruces controlados, respaldan las aseveraciones de que P. × jonesii probablemente desciende de eventos de hibridación entre P. eatonii y P. laevis. El típico P. × jonesii que encontramos en la literatura y en muestras de herbario no se parece al color de la flor de los híbridos F₁ P. eatonii × P. laevis de nuestros cruces control. Sin embargo, en los subsecuentes retrocruzamientos controlados de los híbridos F₁ a P. eatonii, hallamos morfotipos florals y colores de corola coincidentes con las descripciones previas de P. × jonesii. También, observamos muchos híbridos con corolas de colores más pálidos, tales como rosa claro, amarillo rosado y lavanda, que no están documentados en la literature o en ejemplares de herbario.Muestreos de campo relacionados a la variación del color natural de las poblaciónes de P. × jonesii también, revelaron una mayor variación respecto al color de las flores anteriormente reportadas, que deben considerarse como parte de este taxón híbrido, aunque los colores florales predominantes continúen siendo “rosa de Tyria”, “violeta amaranto” y “rojo avioletado a rojo oscuro”, lo cual indicaría un sesgo selectivo. Sugerimos que la preferencia de los polinizadores por las flores de color rojo oscuro a morado puede ser la responsable de este fenómeno.

Recommended Citation

Crump, W. Wesley; Stettler, Jason M.; Johnson, Robert L.; Anderson, Chris D.; Harrison, Sarah; Meservey, Lindsey M.; and Stevens, Mikel R. (2020) "Flower color variation in Jones’ penstemon, Penstemon × jonesii Pennell (P. eatonii A. Gray × P. laevis Pennell) (Plantaginaceae)," Western North American Naturalist: Vol. 80: No. 2, Article 1.
Available at: https://scholarsarchive.byu.edu/wnan/vol80/iss2/1