# Penstemon
> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Penstemon
> Markdown URL: https://mediated.wiki/source/Penstemon.md
> Source: https://en.wikipedia.org/wiki/Penstemon
> Source revision: 1354818501
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)
{{short description|Genus of plants}}
{{Use mdy dates|cs1-dates=ly|date=July 2020}}
{{automatic taxobox
| image = Penstemon nitidus - Patrick Alexander square.jpg
| image_caption = ''Penstemon nitidus''
| taxon = Penstemon
| authority = [Schmidel](/source/Casimir_Christoph_Schmidel)
| subdivision_ranks = Species
| subdivision = See [List of ''Penstemon'' species](/source/List_of_Penstemon_species).
| synonyms_ref = {{sfn|POWO 2024}}
| synonyms = {{Species list
| Apentostera | Raf. (1837)
| Bartramia | Salisb. (1796)
| Dasanthera | Raf. (1819)
| Elmigera | Rchb. ex Spach (1840)
| Leiostemon | Raf. (1825)
| Lepteiris | Raf. (1837)
}}
}}
'''''Penstemon''''' {{IPAc-en|ˈ|p|ɛ|n|s|t|ᵻ|m|ən}},{{sfn|Brenzel|1995|p=607}} the '''beardtongues''', is a large [genus](/source/genus) of roughly 280 species of flowering plants [native](/source/native_plant) to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America.{{sfn|Jepson|Holmgren|1993|p=1050}}{{sfn|Wetherwax|Holmgren|2012|p=1017}} As well as being the scientific name, penstemon is also widely used as a common name for all ''Penstemon'' species alongside beardtongues.
Formerly placed in the [family](/source/Family_(taxonomy)) [Scrophulariaceae](/source/Scrophulariaceae) by the [Cronquist system](/source/Cronquist_system), new genetic research has placed it in the vastly expanded family [Plantaginaceae](/source/Plantaginaceae). The total number of species is disagreed upon due to ongoing research into if some of the named species are actually subspecies or illegitimate concepts of previously described species.
==Description==
[[File:Penstemon eriantherus var. whitedii 1.jpg|right|thumb|A prominent, often hairy, staminode is the most distinctive feature of this genus, as in these ''[Penstemon eriantherus](/source/Penstemon_eriantherus)'' var. ''whitedii'' flowers]]
They have [opposite](/source/opposite_leaves) (rarely alternate or whorled), two-lipped [flower](/source/flower)s with petals fused into a 2-lipped, 5-lobed tube extending into an opening called the throat, and fruits called seed [capsule](/source/Capsule_(fruit))s.{{sfn|Freeman|2021}} The most distinctive features of the genus are the prominent [staminode](/source/staminode), an infertile [stamen](/source/stamen), and the often densely bearded [https://gobotany.nativeplanttrust.org/glossary/p/#:~:text=palate,blocks%20the%20mouth. palate].{{sfn|Taylor|1992|p=50}} The staminode takes a variety of forms in the different species; while it is typically a long straight filament extending to the mouth of the corolla, some are longer and extremely hairy, giving the general appearance of an open mouth with a fuzzy tongue protruding and inspiring the common name of "beardtongue".{{sfn|Taylor|1992|p=50}}
Most penstemons form a durable woody stem (a [caudex](/source/caudex)) and have persistent [basal leaves](/source/Leaf), but some are fully [deciduous](/source/deciduous) [perennials](/source/perennial_plant), the remainder being [shrubs](/source/shrubs) or subshrubs.{{sfn|Lindgren|Wilde|American Penstemon Society|2003|p=7}} Heights can range from 10 cm to as much as 3 meters. Along with their variable growth forms, the penstemons have highly variable leaves, often with different leaf shapes and arrangements on different parts of the same plant.[{{Cite web |title=Penstemon - FNA |url=https://floranorthamerica.org/Penstemon |access-date=2025-12-03 |website=floranorthamerica.org}}] Some species have highly reduced, needle-like leaves and others broad and rounded leaves, with their texture also running the range of hairy to hairless/[glabrous](/source/Glabrousness).{{sfn|Lindgren|Wilde|American Penstemon Society|2003|p=11}}{{sfn|Nold|1999|p=38}} In the view of ''Penstemon'' expert Robert Nold, the defining evolutionary characteristic of the genus is adaptation to drought, as demonstrated by their numbers and diversity in the interior west of North America.{{sfn|Nold|1999|p=53–54}}
Their distinctive flowers have fused petals shaped like a funnel or tube, [distally](/source/distally) extending into a wider mouth. At the opening of the flowers the petals are {{plantgloss|bilabiate}}, with a larger lip with three lobes towards the bottom of the flower and the smaller on the upper side with two lobes.{{sfn|Heil|O'Kane, Jr.|Reeves|Clifford|2013|p=715}} Floral colors are quite varied with white, blue, violet, purple, pink, magenta, and red all being common. Much more rarely they may be yellow, though often only a pale shade of cream or ivory.{{sfn|Wolfe Lab 2023}} The most frequent colors are shades of blue. The inside of the flowers and lips are very often marked by [nectar guide](/source/nectar_guide)s in a distinctive hue, and the interior of the flower may also be a different color than the exterior.{{sfn|Heil|O'Kane, Jr.|Reeves|Clifford|2013|p=715}} Relatively little is known about toxicity in penstemons and there are no reports of poisonings. However, species such as [dusky penstemon](/source/dusky_penstemon) (''Penstemon whippleanus'') are known to contain several alkaloids.{{sfn|Burrows|Tyrl|2012|p=884}}
The one Asiatic species previously treated in ''Penstemon'' is now placed in a separate genus ''[Pennellianthus](/source/Pennellianthus)''. This leaves ''Penstemon'' a mostly [Nearctic](/source/Nearctic_realm) genus, with a few [neotropical](/source/neotropical) species.{{sfn|Nold|1999|p=19}} Although widespread across North America, and found in habitats ranging from open desert to moist forests, and up to alpine zones,{{sfn|Lindgren|Wilde|American Penstemon Society|2003|p=7}} they are not typically common within their range.
==Taxonomy==
thumb|right|Firecracker penstemon (''Penstemon eatonii'')
thumb|right|Davidson's Penstemon (''Penstemon davidsonii'')
The ''Penstemon'' genus is placed in the large plantain family, Plantaginaceae, alongside others in tribe [Cheloneae](/source/Cheloneae). Prior to 2005 they had usually been included in the figwort family, Scrophulariaceae.{{sfn|Olmstead|de Pamphilis|Wolfe|Young|2001}}{{sfn|Oxelman|Kornhall|Olmstead|Bremer|2005}}
''Penstemon'' has been subdivided into six subgenera by using [anther](/source/Stamen) [dehiscence](/source/Dehiscence_(botany)) patterns. Subgenera ''Cryptostemon'' and ''Dissecti'' each contain one species. As traditionally defined, subgenus ''Penstemon'' contains about 128 species, subgenus ''Habroanthus'' contains about 50, subgenus ''Saccanthera'' has about 28 species, and subgenus ''Dasanthera'' contains nine. Genetic analysis by Andrea D Wolfe et al. indicates that while some of the previously identified subgenera are natural groupings, many are hopelessly confused.{{sfn|Wolfe|Randle|Datwyler|Morawetz|2006}} Garden experiments by Glen Moore and other scientists have shown that even very distantly related species in the genus are capable of hybridizing. However, due to geographic isolation and soil preferences keeping species apart hybrids are rare in nature.{{sfn|Welsh et al. 1987|p=579}}
===History===
[John Mitchell](/source/John_Mitchell_(geographer)) published the first scientific description in 1748; although he only named it as ''Penstemon'', researchers David Way, Peter James, and Robert Nold identify it as ''[Penstemon laevigatus](/source/Penstemon_laevigatus)''.{{sfn|Way|James|1998|p=16–17}}{{sfn|Nold|1999|p=58–59}} [Linnaeus](/source/Carl_Linnaeus) then included it in his 1753 publication, as ''Chelone pentstemon'', altering the spelling to better correspond to the notion that the name referred to the unusual fifth stamen (Greek "penta-", five). The botanist [Casimir Schmidel](/source/Casimir_Christoph_Schmidel) published a description of the species in 1763, and for this reason he is given priority in botanical publication.{{sfn|Nold|1999|p=58–59}} Mitchell's work was reprinted in 1769, continuing with his original spelling, and this was ultimately accepted as the official form, although ''Pentstemon'' continued in use into the 20th century.{{sfn|Way|James|1998|p=17–18}} In addition, a rare spelling of ''Pentastemon'' is occasionally found in older works.{{sfn|Heil|O'Kane, Jr.|Reeves|Clifford|2013|p=715}}
Although several more species were found in the early 18th century, they continued to be classified in ''[Chelone](/source/Chelone_(plant))'' until 1828 in some publications. The period of 1810 to 1850 increased the number of known species from 4 to 63, as expeditions traveled through Mexico and the western United States, followed by another 100 up to 1900, although not all these species remained classified as ''Penstemon''.{{sfn|Way|James|1998|p=18–19}}
The American members of the genus were extensively revised by [David D. Keck](/source/David_D._Keck) between 1932 and 1957{{sfn|Bennett|Lodewick|Lodewick|1987|p=15–16}} and Richard Straw did similar work on the Mexican species slightly later.{{sfn|Way|James|1998|p=19}} In 1960 the important book ''Penstemon Nomenclature'' was published by American Penstemon Society president Ralph Bennett with the advice of Keck. This book was updated and republished with the Robin Lodewick in 1980 and continued to be an important source of information about the genus through the year 2000.{{sfn|Way|James|1998|p=19}}
Fieldwork in the remote parts of the [Great Basin](/source/Great_Basin) during the 20th century brought the total number of species known to over 270, though some of this total may be errors or now extinct species.{{sfn|Way|James|1998|p=19}}
===Species===
{{Main list|List of Penstemon species}}
There are at least [281 species](/source/List_of_Penstemon_species) that are valid according to both [World Flora Online](/source/World_Flora_Online) (WFO) and [Plants of the World Online](/source/Plants_of_the_World_Online) (POWO) as of 2024.{{sfn|WFO 2024}}{{sfn|POWO 2024}} In addition there are at least [five naturally occurring hybrids](/source/List_of_Penstemon_species), and seven recognized by POWO.{{sfn|WFO 2024}}{{sfn|POWO 2024}} In addition there are [five other additional species](/source/List_of_Penstemon_species) that are recognized by WFO.{{sfn|WFO 2024}} Though there is agreement between POWO and WFO on many species, many additional species are considered valid by other sources. For example, there are 239 with full descriptions in the [Flora of North America](/source/Flora_of_North_America) alone.{{sfn|Freeman|2021}}
==Ecology==
Most penstemon species have one of two [pollination syndrome](/source/pollination_syndrome)s: adaptation to [hummingbird](/source/hummingbird)s or to [bees](/source/bees). The species relying on hummingbirds typically have flowers that are red or magenta, have narrow tubes, and that produce larger amounts of [nectar](/source/nectar) from nectaries located deep inside the throat of the corolla. Bee-adapted species more often have blue or purple flowers, wide floral tubes, a longer lower lip for bees to land on, and produce less nectar. Adaptation to bees as pollinators is an ancestral trait for penstemons, but the derived trait of instead adapting to hummingbirds has emerged an estimated fifteen to twenty times over a relatively short evolutionary history.{{sfn|Katzer|Wessinger|Hileman|2019|p=377}}
==Distribution==
Penstemon species are found in most of North America.{{sfn|Freeman|2021}} One species, ''[Penstemon gentianoides](/source/Penstemon_gentianoides)'', has a native range that extends as far south as [Guatemala](/source/Guatemala) and has been introduced to [Costa Rica](/source/Costa_Rica). Another species, ''[Penstemon gormanii](/source/Penstemon_gormanii)'', grows in the [Northwest Territories](/source/Northwest_Territories) of Canada. No members of the genus have been known to grow natively in [Nunavut](/source/Nunavut), or east of Quebec in Canada. In addition to the same species as found in the Northwest Territories, two others also grow in parts of Alaska, ''[Penstemon procerus](/source/Penstemon_procerus)'' and ''[Penstemon serrulatus](/source/Penstemon_serrulatus)''.{{sfn|Hassler 2024}} Most of its species are found in the [Nearctic](/source/Nearctic_realm) botanical realm, but with a few species also found in the North American portion of the [Neotropics](/source/Neotropical_realm).{{sfn|Wolfe Lab 2023}} There are 70 species found in the state of Utah, more than anywhere else in its range and making this its [center of diversity](/source/center_of_diversity).{{sfn|Way|James|1998|p=14}}
==Horticulture==
Although penstemons are native to the Americas, Europe has traditionally been far more active in their hybridization with hundreds of hybrids developed since the early 19th century. The first offer of seeds for sale as by John Fraser in 1813.{{sfn|Way|James|1998|p=18}} The earliest development is somewhat shrouded in mystery; for instance Flanagan & Nutting's 1835 catalog mentions a 'Penstemon Hybridum' but does not describe it.{{sfn|Way|James|1998|p=20}}
By 1860, a half-dozen French growers are known to have developed hybrids, most notably [Victor Lemoine](/source/Victor_Lemoine), while in 1857 the German [Wilhelm Pfitzer](/source/Wilhelm_Pfitzer) listed 24 varieties. In 1861 the British [Royal Horticultural Society](/source/Royal_Horticultural_Society) held trials in which 78 varieties were entered. The Scottish firm of John Forbes first offered penstemons in 1870, eventually becoming the biggest grower in the world; in 1884 their catalog listed 180 varieties. By 1900 Forbes had offered 550 varieties, while Lemoine had developed nearly 470 by the time of his death in 1911. Few of these have survived to the present day.{{sfn|Way|James|1998|p=22–24}}
A number of different species have been used in the hybridization process, notably ''[Penstemon cobaea](/source/Penstemon_cobaea)'' and ''[Penstemon hartwegii](/source/Penstemon_hartwegii)''.{{sfn|Way|James|1998|p=20,22,24}}
The American Penstemon Society was formed in 1946 to promote both horticultural and botanical interest, and is now the [International Cultivar Registration Authority](/source/International_Cultivar_Registration_Authority) for the genus.{{sfn|Way|James|1998|p=153}}
In North America, penstemons are often used in [xeriscape](/source/xeriscape) gardening, as many are native to desert or alpine regions and quite hardy.{{sfn|Wolfe Lab 2023}}
===Cultivars===
The following species and cultivars have gained the Royal Horticultural Society's [Award of Garden Merit](/source/Award_of_Garden_Merit):-[{{cite web | url = https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 75 | publisher = Royal Horticultural Society | access-date = 2018-04-22}}]
{{div col|colwidth=30em}}
* 'Andenken an Friedrich Hahn'[{{cite web|url=https://www.rhs.org.uk/Plants/46091/Penstemon-Andenken-an-Friedrich-Hahn/Details |title=RHS Plant Selector Penstemon 'Andenken an Friedrich Hahn' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (deep red)
* 'Beech Park'[{{cite web|url=https://www.rhs.org.uk/Plants/53326/Penstemon-Beech-Park/Details|title=RHS Plant Selector Penstemon 'Beech Park' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (pink/white)
* 'Connie's Pink'[{{cite web|url=https://www.rhs.org.uk/Plants/111627/Penstemon-Connie-s-Pink/Details |title=RHS Plant Selector Penstemon 'Connie's Pink' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (rose pink)
* 'Evelyn'[{{cite web|url=https://www.rhs.org.uk/Plants/97126/Penstemon-Evelyn/Details|title=RHS Plant Selector Penstemon 'Evelyn' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (rose pink)
* 'George Home'[{{cite web|url=https://www.rhs.org.uk/Plants/84025/Penstemon-George-Home/Details |title=RHS Plant Selector Penstemon 'George Home' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (red/white)
* 'Hewell Pink Bedder'[{{cite web|url=https://www.rhs.org.uk/Plants/57085/Penstemon-Hewell-Pink-Bedder/Details |title=RHS Plant Selector Penstemon 'Hewell Pink Bedder' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (pink/white)
* '[Hidcote](/source/Hidcote_Manor_Garden) Pink'[{{cite web|url=https://www.rhs.org.uk/Plants/42268/Penstemon-Hidcote-Pink/Details |title=RHS Plant Selector Penstemon 'Hidcote Pink' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}]
* '[Margery Fish](/source/Margery_Fish)'[{{cite web|url=https://www.rhs.org.uk/Plants/72813/Penstemon-Margery-Fish/Details |title=RHS Plant Selector Penstemon 'Margery Fish' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (purple/blue)
* 'Maurice Gibbs'[{{cite web|url=https://www.rhs.org.uk/Plants/109585/Penstemon-Maurice-Gibbs/Details |title=RHS Plant Selector Penstemon 'Maurice Gibbs' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=27 January 2021}}] (purple-red/white)
* 'Osprey'[{{cite web | url = https://www.rhs.org.uk/Plants/83799/Penstemon-Osprey-(Bird-Series)/Details| title = RHS Plantfinder - ''Penstemon'' 'Osprey' (Bird Series) | access-date = 27 January 2021}}] (pink/white)
* ''P. hartwegii''[{{cite web | url = https://www.rhs.org.uk/Plants/66754/i-Penstemon-hartwegii-i/Details
| title = RHS Plantfinder - ''Penstemon hartwegii'' | access-date = 2018-04-22}}] (scarlet)
* ''P. isophyllus''[{{cite web|url=https://www.rhs.org.uk/Plants/12465/Penstemon-isophyllus/Details |title=RHS Plant Selector Penstemon isophyllus AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=28 January 2021}}] (pale pink)
* ''P. pinifolius'' 'Wisley Flame'[{{cite web | url = https://www.rhs.org.uk/Plants/93160/i-Penstemon-pinifolius-i-Wisley-Flame/Details
| title = RHS Plantfinder - ''Penstemon pinifolius'' 'Wisley Flame' | access-date = 2018-04-22}}] (orange-red)
* ''P. rupicola''[{{cite web | url = https://www.rhs.org.uk/Plants/12477/i-Penstemon-rupicola-i/Details
| title = RHS Plantfinder - ''Penstemon rupicola'' | access-date = 2018-04-22}}] (pink)
* 'Port Wine'[{{cite web|url=https://www.rhs.org.uk/Plants/91495/Penstemon-Port-Wine/Details|title=RHS Plant Selector Penstemon 'Port Wine' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=28 January 2021}}] (deep red/white)
* 'Raven'[{{cite web|url=https://www.rhs.org.uk/Plants/61638/Penstemon-Raven-(Bird-Series)/Details |title=RHS Plant Selector Penstemon 'Raven' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=28 January 2021}}] (purple/white)
* 'Rich Ruby'[{{cite web | url = https://www.rhs.org.uk/Plants/80875/i-Penstemon-i-Rich-Ruby/Details | title = RHS Plantfinder - ''Penstemon'' 'Rich Ruby' | access-date = 2018-04-22}}]
* 'Roy Davidson'[{{cite web|url=https://www.rhs.org.uk/Plants/120167/Penstemon-procerus-Roy-Davidson/Details |title=RHS Plant Selector Penstemon procerus 'Roy Davidson' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=30 January 2021}}] (pink/white)
* 'Rubicundus'[{{cite web|url=https://www.rhs.org.uk/Plants/49363/Penstemon-Rubicundus/Details|title=RHS Plant Selector Penstemon 'Rubicundus' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=30 January 2021}}] (red/white)
* 'Schoenholzeri'[{{cite web|url=https://www.rhs.org.uk/Plants/67036/Penstemon-Schoenholzeri/Details|title=RHS Plant Selector Penstemon 'Schoenholzeri' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=30 January 2021}}] (red)
* 'Sour Grapes'[{{cite web|url=https://www.rhs.org.uk/Plants/89778/Penstemon-Sour-Grapes-M-Fish/Details|title=RHS Plant Selector Penstemon 'Sour Grapes' M. Fish AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=30 January 2021}}] (purple/blue)
* 'Stapleford Gem'[{{cite web|url=https://www.rhs.org.uk/Plants/95191/Penstemon-Stapleford-Gem/Details |title=RHS Plant Selector Penstemon 'Stapleford Gem' AGM / RHS Gardening |publisher=Apps.rhs.org.uk |access-date=30 January 2021}}] (purple/blue)
{{div col end}}
Others include 'Dark Towers', developed by Dale Lindgren at the [University of Nebraska–Lincoln](/source/University_of_Nebraska%E2%80%93Lincoln).[[http://www.waltersgardens.com/plants/General-Perennial/1942_PenstemonDark-TowersPP20013.aspx Walters Gardens. Penstemon 'Dark Towers' PP20013]]
== See also ==
* [HMS ''Pentstemon''](/source/HMS_Pentstemon)
==References==
===Citations===
{{Reflist}}
===Sources===
{{Refbegin}}
* {{cite book |last1=Bennett |first1=Ralph W. |last2=Lodewick |first2=Kenneth |last3=Lodewick |first3=Robin |title=Penstemon Nomenclature |date=1987 |publisher=American Penstemon Society |location=Eugene, Oregon |pages=4–6, 15–16 |oclc=21365444 |edition=2nd |language=en}}
* {{cite book |editor1-last=Brenzel |editor1-first=Kathleen Norris |title=Sunset Western Garden Book |date=1995 |publisher=Sunset Publishing Corporation |location=Menlo Park, California |isbn=978-0-376-03851-7 |edition=40th Anniversary |url=https://archive.org/details/westerngardenboo00suns |access-date=9 July 2024}}
* {{Cite book |last1=Burrows |first1=George Edward |last2=Tyrl |first2=Ronald J. |date=2012 |title=Toxic Plants of North America |edition=2nd |location=Hoboken, New Jersey |publisher=Wiley-Blackwell |doi=10.1002/9781118413425.ch57 |isbn=978-0-813-82034-7 |oclc=815970198}}
* {{cite book |last1=Heil |first1=Kenneth D. |last2=O'Kane, Jr. |first2=Steve L. |last3=Reeves |first3=Linda Mary |last4=Clifford |first4=Arnold |title=Flora of the Four Corners Region : Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, and Utah |date=2013 |publisher=Missouri Botanical Garden |location=St. Louis, Missouri |url=https://archive.org/details/mobot31753003888887 |access-date=14 July 2024 |language=en}}
* {{cite book |title=The Jepson Manual: Higher Plants of California |last1=Jepson |first1=Willis Linn |author-link1=Willis Linn Jepson |last2=Holmgren |first2=Noel H. |year=1993 |orig-year=1925 |editor-last=Hickman |editor-first=James C. |editor-link=James C. Hickman |edition=First |location=[Berkeley, California](/source/Berkeley%2C_California) |publisher=University of California Press |isbn=0-52008255-9 |url-access=registration |url=https://archive.org/details/jepsonmanualhigh00hick }}
* {{cite book |last1=Lindgren |first1=Dale Tennis |last2=Wilde |first2=Ellen M. |last3=American Penstemon Society |title=Growing Penstemons: Species, Cultivars, and Hybrids |date=2003 |publisher=Infinity Publishing |location=Haverford, Pennsylvania |isbn=0-7414-1529-1 |oclc=54110971 |url=https://archive.org/details/growingpenstemon0000lind |access-date=10 July 2024 |language=en}}
* {{cite book |last1=Nold |first1=Robert |title=Penstemons |date=1999 |publisher=Timber Press |location=Portland, Oregon |isbn=0-88192-429-6 |oclc=44962199 |edition=1st |language=en}}
* {{cite book |last1=Taylor |first1=Ronald J. |title=Sagebrush Country : A Wildflower Sanctuary |date=1992 |publisher=Mountain Press Publishing Company |location=Missoula, Montana |isbn=0-87842-280-3 |oclc=1005485280 |edition=1st |url=https://archive.org/details/sagebrushcountry00tayl |access-date=10 July 2024 |language=en}}
* {{cite book |last1=Way |first1=David |last2=James |first2=Peter |title=The Gardener's Guide to Growing Penstemons |date=1998 |publisher=David & Charles Publishers ; Timber Press |location=Newton Abbot, England ; Portland, Oregon |isbn=978-0-88192-424-4 |oclc=38879416 |edition=1st |url=https://archive.org/details/gardenersguideto00wayd |access-date=10 July 2024 |language=en}}
* {{Cite book |last1=Neese |first1=Elizabeth C. |chapter=Penstemon |editor-last1=Welsh |editor-first1=Stanley L. |editor-link1=Stanley Larson Welsh |editor-last2=Atwood |editor-first2=N. Duane |editor-last3=Goodrich |editor-first3=Sherel |editor-last4=Higgins |editor-first4=Larry C. |date=1987 |title=A Utah Flora |url=https://archive.org/details/utahflora0000unse/page/243 |url-access=registration |series=Great Basin Naturalist Memoirs, No. 9 |language=en |edition=First |location=Provo, Utah |publisher=Brigham Young University |jstor=23377658 |oclc=9986953694 |access-date=18 February 2025 |ref={{sfnref|Welsh et al. 1987}}}}
* {{cite book |last1=Wetherwax |first1=Margriet |last2=Holmgren |first2=Noel H. |title=The Jepson Manual, Vascular Plants of California, Thoroughly Revised and Expanded |year=2012 |editor1-last=Baldwin |editor1-first=Bruce G. |editor2-last=Goldman |editor2-first=Douglas |editor3-last=Keil |editor3-first=David J. |editor4-last=Patterson |editor4-first=Robert |editor5-last=Rosatti |editor5-first=Thomas J. |editor6-last=Wilken |editor6-first=Dieter |edition=Second |location=Berkeley, California |publisher=University of California Press |isbn=9780520253124}}
{{Refend}}
;Journal articles
{{refbegin}}
* {{Cite journal |last1=Katzer |first1=Amanda M. |last2=Wessinger |first2=Carolyn A. |last3=Hileman |first3=Lena C. |date=July 2019 |title=Nectary size is a pollination syndrome trait in ''Penstemon'' |journal=New Phytologist |language=en |volume=223 |issue=1 |pages=377–384 |doi=10.1111/nph.15769 |doi-access=free |issn=0028-646X |jstor=26675987 |pmid=30834532 |pmc=6593460}}
* {{Cite journal |last1=Olmstead |first1=Richard G. |last2=de Pamphilis |first2=Claude W. |last3=Wolfe |first3=Andrea D. |last4=Young |first4=Nelson D. |last5=Elisons |first5=Wayne J. |last6=Reeves |first6=Patrick A. |date=February 2001 |title=Disintegration of the Scrophulariaceae |journal=American Journal of Botany |language=en |volume=88 |issue=2 |pages=348–361 |doi=10.2307/2657024 |jstor=2657024 |pmid=11222255 |doi-access=free}}
* {{Cite journal |last1=Oxelman |first1=Bengt |last2=Kornhall |first2=Per |last3=Olmstead |first3=Richard G. |last4=Bremer |first4=Birgitta |date=May 2005 |title=Further disintegration of Scrophulariaceae |journal=Taxon |language=en |volume=54 |issue=2 |pages=411–425 |doi=10.2307/25065369 |jstor=25065369 |issn=0040-0262}}
* {{cite journal |last1=Wolfe |first1=Andrea D. |last2=Randle |first2=Christopher P. |last3=Datwyler |first3=Shannon L. |last4=Morawetz |first4=Jeffery J. |last5=Arguedas |first5=Nidia |last6=Diaz |first6=Jose |title=Phylogeny, taxonomic affinities, and biogeography of ''Penstemon'' (Plantaginaceae) based on ITS and cpDNA sequence data |journal=American Journal of Botany |date=November 2006 |volume=93 |issue=11 |pages=1699–1713 |doi=10.3732/ajb.93.11.1699 |pmid=21642115 |url=https://www.researchgate.net/publication/51192402}}
{{Refend}}
;Web sources
{{refbegin}}
* {{cite web |last1=Freeman |first1=Craig C. |title=''Penstemon'' - FNA |url=http://floranorthamerica.org/Penstemon |website=Flora of North America |access-date=9 July 2024 |date=8 December 2021}}
* {{cite web |last1=Hassler |first1=Michael |title=Synonymic Checklist and Distribution of the World Flora. Version 19.4 |url=https://www.worldplants.de/ |website=World Plants |access-date=10 July 2024 |language=en |date=30 June 2024 |ref={{sfnref|Hassler 2024}}}}
* {{Cite POWO |last1=POWO | author-link1=Plants of the World Online |year=2024 |id=30000992-2 |title=''Penstemon'' Schmidel | access-date=9 July 2024 |ref={{sfnref|POWO 2024}}}}
* {{cite web |last1=WFO |author-link1=World Flora Online |title=''Penstemon'' Schmidel |url=http://www.worldfloraonline.org/taxon/wfo-4000028548 |website=www.worldfloraonline.org |access-date=4 April 2024 |date=2024 |ref={{sfnref|WFO 2024}}}}
* {{cite web |title=''Penstemon'' |url=https://wolfelab.asc.ohio-state.edu/penstemon.php |website=Wolfe Lab |publisher=Ohio State University |access-date=14 July 2024 |language=en |date=2023 |ref={{sfnref|Wolfe Lab 2023}}}}
{{Refend}}
== Further reading ==
* Way, D. and P. James. ''The Gardener's Guide to Growing Penstemons''. David & Charles Publishers. 1998. {{ISBN|0-7153-0550-6}}
* Nold, Robert. ''Penstemons''. Timber Press. 1999. {{ISBN|0-88192-429-6}}
* Lindgren, Dale T. ''Growing penstemons : species, cultivars, and hybrids''. Haverford, PA: Infinity Pub. 2003. {{ISBN|0-7414-1529-1}}.
== External links ==
* [http://www.penstemons.org/ American Penstemon Society]
* [https://wolfelab.asc.ohio-state.edu/database Wolfe Lab Penstemon Database]
{{Commons category|Penstemon}}
{{Taxonbar|from=Q809265}}
Category:Penstemon
Category:Plantaginaceae genera
---
Adapted from the Wikipedia article [Penstemon](https://en.wikipedia.org/wiki/Penstemon) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Penstemon?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.