Penstemon laricifolius

{{Speciesbox

| image = Penstemon laricifolius - Patrick Alexander 01.jpg

| image_alt = In front of a gray rock growing from rocky, slightly orange soil, a light green plant with thin stems and very narrow, grasslike leaves has many bright pink tubular flowers with five wide lobes at the opening and darker flower buds higher up on the stems.

| image_caption = Bighorn Basin, Hot Springs County, Wyoming

| status = {{TNCStatus}}

| status_system = TNC

| status_ref = {{sfn|NatureServe 2025a}}

| genus = Penstemon

| species = laricifolius

| authority = Hook. & Arn.

| subdivision_ranks = Varieties

| subdivision_ref = {{sfn|POWO 2025a}}

| subdivision = {{Species list

| P. laricifolius var. exilifolius |

| P. laricifolius var. laricifolius |

}}

| synonyms_ref = {{sfn|POWO 2025b}}{{sfn|POWO 2025c}}

| synonyms = {{Collapsible list | {{Species list

| Penstemon exilifolius |

| Penstemon filifolius |

}}

Penstemon laricifolius, the larchleaf penstemon, is a small herbaceous plant from the northern Rocky Mountain states of Montana, Wyoming, and Colorado. It grows in a form like a small tuft of grass and has very narrow leaves. In southern parts of its range its funnel shaped flowers are more white or pale and in the north they are deeper pink or purple. It is infrequently grown as a cultivated plant dry rock gardens.

Description

Larchleaf penstemon is small herbaceous plant with stems that reach {{convert|10 to 30|cm|0|sp=us}} in height at full size. They are caespitose in form, resembling a tuft of grass.{{sfn|Freeman 2020a}}

Its leaves are may be basal or cauline, attached directly to the base of the plant or to its stems, and are hairless except for rarely at base usually on the edges of the leaves. The basal leaves are narrow and short, measuring just 15 to 40 millimeters long and usually less than 20 mm with a width of 0.5 to 1.5 mm. The leaves attach directly to the plant without a leaf stem with the base more or less clasping. Each stem will have three to seven pairs of leaves attached on opposite sides of the stem. These are even smaller, just 11 to 35 mm long and 0.3 to 1 mm wide. They have bases that taper or clasp the stems and a narrow point.{{sfn|Freeman 2020a}}

File:Penstemon laricifolius var. laricifolius - 52283129032.jpg

The species as a whole has a wide range of flower colors from white to purple, including pink, violet, and greenish, but always lacking nectar guidelines.{{sfn|Freeman 2020a}}{{sfn|Nelson|Williams|1992|p=305}} The flowers are held on the upper parts of flowering stems, but the outermost stems may bend to the ground giving the appearance of having flowers all the way down the plant.{{sfn|Lindgren & Wilde 2003|p=56}} The inflorescence is the upper {{cvt|3 to 15|cm}} of the stem with three to seven groups of flower each with one or two attachment points and each of these cymes with one to three flowers. The flowers are funnel shaped and range in length from 9 to 18 mm. The flower's tube is 4–5 mm and gets gradually wider towards the opening without a constriction at the mouth. Inside the flower it is covered with a moderate amount of yellow hairs. The stamens do not reach outside the flower and the staminode also is inside the flower or just reaches the opening. It is covered in yellow or yellow-orange hairs.{{sfn|Freeman 2020a}} Variety exilifolius blooms as early as June and as late as August while variety laricifolius will also bloom in May.{{sfn|Freeman 2020b}}{{sfn|Freeman 2020c}} The bloom period can vary significantly from year to year,{{sfn|Tepedino||Stanton|1980|pp=201, 206, 213}} the season continuing in wet year and being shortened in years of drought.{{sfn|Heidel|Handley|2007|p=34}}

The fruit is a capsule that measures 4–5 mm tall and 2.5–4 mm wide.{{sfn|Freeman 2020a}}

It is somewhat similar in appearance to rock penstemon (Penstemon gairdneri) and lives in similar habitats, but rock penstemon is found in the sagebrush steppes of Washington, Oregon, and Idaho.{{sfn|Taylor|1992|p=52}}

Taxonomy

Penstemon laricifolius was scientifically described and named in 1839 by the botanists William Jackson Hooker and George Arnott Walker Arnott.{{sfn|POWO 2025a}} Though the type specimen was described by Hooker and Arnott as being found near "Snake Fort, Snake County" in Idaho, later botanists like David D. Keck doubt that it was collected in Idaho.{{sfn|Keck|1937|p=380}}{{sfn|Hooker|Walker-Arnott|Beechey|1841|p=376}} The collection was probably by the trapper John McLeod a friend of William Fraser Tolmie.{{sfn|Heidel|Handley|2007|p=11}}

It is classified in the Penstemon genus in the veronica family.{{sfn|POWO 2025a}} Analysis of the DNA indicates that it is related to the species in section Cristati such as Penstemon breviculus, Penstemon triflorus, and Penstemon cobaea.{{sfn|Wessinger et al. 2016|pp=915–916}} It genome contains 558 mega base pairs, towards the smaller end of species surveyed in the Penstemon genus.{{sfn|Broderick et al. 2011|pp=164, 170}}

=Varieties=

Penstemon laricifolius has two varieties according to Plants of the World Online.{{sfn|POWO 2025a}} There are populations in Wyoming which have a mix of characteristics.{{sfn|Freeman 2020a}} Known locations include two in the Bighorn National Forest and one in Medicine Bow-Routt National Forest.{{sfn|Heidel|Handley|2007|p=3}}

==''Penstemon laricifolius'' var. ''exilifolius''==

This variety was described in 1901 by Aven Nelson as a species named Penstemon exilifolius. In 1924 Edwin Blake Payson described it as a variety of Penstemon laricifolius. It was also described as a subspecies by David D. Keck in 1937.{{sfn|POWO 2025b}} Most of this variety grows in the watershed of the Laramie River, largely in southern Wyoming and a small portion of northern Colorado.{{sfn|Freeman 2020b}} The flower may be white, pale pink, or slightly green.{{sfn|Nelson|Williams|1992|p=305}} In the Flora of North America it is defined as having white flowers measuring shorter on average, 9–15 mm, but overlapping with that of variety laricifolius.{{sfn|Freeman 2020a}} It grows at elevations from {{convert|1500 to 2900|m|spell=us}} in sandy or gravelly grasslands and the sagebrush steppe.{{sfn|Freeman 2020b}} It is occasionally called Nelson larchleaf penstemon for Aven Nelson.{{sfn|Heidel|Handley|2007|p=10}}

==''Penstemon laricifolius'' var. ''laricifolius''==

The autonymic variety is the more northerly of the two varieties, growing in central and western Wyoming and in southern Wyoming.{{sfn|Freeman 2020c}} It has longer and darker flowers, pink, violet, or purple in color and measuring 10–18 mm.{{sfn|Freeman 2020a}} It grows at elevations from {{convert|1500 to 2400|m|spell=us}} and like variety exilifolius is associated with grasslands and the sagebrush steppe, but also may be found in pine forest openings.{{sfn|Freeman 2020c}}

=Synonyms=

Penstemon laricifolius has {{table row counter|id=Synonyms}} synonyms of the species or one of its varieties.{{sfn|POWO 2025a}}{{sfn|POWO 2025b}}{{sfn|POWO 2025c}}

class="wikitable sortable mw-collapsible" id="Synonyms" \|+ class="nowrap" \| Table of Synonyms ! Name ! Year ! Rank ! Synonym of: ! Notes
Penstemon exilifolius {{small\|A.Nelson}} \| 1901 \|data-sort-value=A \| species \| var. exilifolius \|data-sort-value=A \| ≡ hom.
Penstemon exilifolius var. desertus {{small\|A.Nelson}} \| 1901 \|data-sort-value=D \| variety \| var. exilifolius \|data-sort-value=B \| = het.
Penstemon filifolius {{small\|Nutt. ex Benth.}} \| 1846 \|data-sort-value=A \| species \| var. laricifolius \|data-sort-value=B \| = het.
Penstemon laricifolius subsp. exilifolius {{small\|(A.Nelson) D.D.Keck}} \| 1937 \|data-sort-value=B \| subspecies \| var. exilifolius \|data-sort-value=A \| ≡ hom.
Penstemon laricifolius subsp. typicus {{small\|D.D.Keck}} \| 1937 \|data-sort-value=B \| subspecies \| P. laricifolius \|data-sort-value=A \| ≡ hom., not validly publ.
colspan=5 style="text-align: left;" \| Notes: ≡ homotypic synonym ; = heterotypic synonym

class="wikitable sortable mw-collapsible" id="Synonyms"

|+ class="nowrap" | Table of Synonyms

! Name

! Year

! Rank

! Synonym of:

! Notes

Penstemon exilifolius {{small|A.Nelson}}

| 1901

|data-sort-value=A | species

| var. exilifolius

|data-sort-value=A | ≡ hom.

Penstemon exilifolius var. desertus {{small|A.Nelson}}

| 1901

|data-sort-value=D | variety

| var. exilifolius

|data-sort-value=B | = het.

Penstemon filifolius {{small|Nutt. ex Benth.}}

| 1846

|data-sort-value=A | species

| var. laricifolius

|data-sort-value=B | = het.

Penstemon laricifolius subsp. exilifolius {{small|(A.Nelson) D.D.Keck}}

| 1937

|data-sort-value=B | subspecies

| var. exilifolius

|data-sort-value=A | ≡ hom.

Penstemon laricifolius subsp. typicus {{small|D.D.Keck}}

| 1937

|data-sort-value=B | subspecies

| P. laricifolius

|data-sort-value=A | ≡ hom., not validly publ.

colspan=5 style="text-align: left;" | Notes: ≡ homotypic synonym ; = heterotypic synonym

=Names=

The species name, laricifolius, means "with larch like leaves" in botanical Latin.{{sfn|Lindgren & Wilde 2003|p=56}} Similarly, in English it is known by the common name larchleaf pestemon.{{sfn|Taylor|1992|p=52}}

Range and habitat

File:Penstemon laricifolius - Cecelia Alexander 01.jpg

The native range of larchleaf penstemon is from southern Montana through Wyoming to northern Colorado. In Montana it is confined to just Carbon and Big Horn counties, but it grows through much of western Wyoming.{{sfn|NRCS 2025}} In Colorado it grows in just the Laramie River valley in northwestern Larimer County.{{sfn|Freeman 2020b}}

Ecology

Twenty-eight species of bees in four different families have were collected by Vince Tepedino over the course of three years from flowers of Penstemon laricifolius var. exilifolius at two study locations in the Laramie Basin. Though some of the species were not positively identified. The bumblebee species in family Apidae include the white-shouldered bumblebee (Bombus appositus), the two-form bumblebee (Bombus bifarius), the central bumblebee (Bombus centralis), the golden northern bumble bee (Bombus fervidus), the yellow-fronted bumble bee (Bombus flavifrons), the Hunt bumblebee (Bombus huntii), the Nevada bumblebee (Bombus nevadensis), the western bumble bee (Bombus occidentalis), and the red-belted bumblebee (Bombus rufocinctus). Others in the same family include Anthophora albata, Ceratina nanula, and Ceratina neomexicana. In family Andrenidae, the mining bees, visitors include the Costilla miner bee (Andrena costillensis), the streaked miner bee (Calliopsis zebrata), and the grassland miner bee (Pseudopanurgus didirupa). The family of solitary bees Megachilidae species include Anthidium tenuiflorae, Ashmeadiella gillettei, Osmia brevis, Osmia bruneri, Osmia giliarum, Osmia integra, and Osmia sculleni. In family Halictidae, the sweat bees, the three species Lasioglossum pruinosum, Lasioglossum semicaeruleum, and Halictus confusus.{{sfn|Heidel|Handley|2007|pp=34, 36}}

=Conservation=

The conservation organization NatureServe evaluated Penstemon laricifolius in 1984 and rated it as apparently secure (G4) at the global level. They similarly rated it at the state level as apparently secure (S4) in Wyoming. In Montana they rated it as vulnerable (S3) and imperiled (S2) in Colorado.{{sfn|NatureServe 2025a}}

Separately, NatureServe evaluated Penstemon laricifolius var. exilifolius in 2017, though with the rank of subspecies. They found it to be vulnerable (T3) at the global level. The species has about 20 existing populations containing 13,000 plants. Since the 1950s at least 11 populations have been destroyed. Ongoing threats to the variety include residential development, invasion of non-native species, and recreation.{{sfn|NatureServe 2025b}}

Cultivation

Larchleaf pestemon is grown in rock gardens, but often has to be grown in garden troughs to be kept more evenly dry than in ground beds are able to provide.{{sfn|Kelaidis|2003|p=247}} Though it is adapted to very dry conditions it requires moisture in the spring to flower.{{sfn|Lindgren & Wilde 2003|p=56}} The seeds of the species show some need for cold moist stratification to break dormancy. Only 10% of seeds sprouted when planted at {{convert|70|F|C|order=flip}} while 56% sprouted after being held at {{convert|40|F|C|order=flip}} for ten to twelve weeks first.{{sfn|Love|Akins|2020|}}

References

=Citations=

=Sources=

;Books

{{Cite book |last1=Hooker |first1=William Jackson |author-link1=William Jackson Hooker |last2=Walker-Arnott |first2=George Arnott |author-link2=George Arnott Walker Arnott |last3=Beechey |first3=Frederick William |author-link3=Frederick William Beechey |date=1841 |title=The Botany of Captain Beechey's Voyage : Comprising an Account of thePplants Collected by Messrs. Lay and Collie, and Other Officers of the Expedition, During the Voyage to the Pacific and Behring's Strait, Performed in His Majesty's Ship Blossom, Under the Command of Captain F. W. Beechey ... in the Years 1825, 26, 27, and 28 |url=https://www.biodiversitylibrary.org/page/404437 |language=en |edition=First |location=London |publisher=Henry G. Bohn |oclc=718480806 |url-status=live |archive-url=https://archive.org/details/mobot31753000407004 |archive-date=20 December 2011 |access-date=15 February 2025}}
{{cite book |last1=Lindgren |first1=Dale Tennis |last2=Wilde |first2=Ellen |last3=American Penstemon Society |date=2003 |title=Growing Penstemons : Species, Cultivars, and Hybrids |url=https://archive.org/details/growingpenstemon0000lind/page/56 |url-access=registration |language=en |edition=First |location=Haverford, Pennsylvania |publisher=Infinity Publishing |isbn=978-0-7414-1529-5 |lccn=2004272722 |oclc=54110971 |access-date=12 February 2025 |ref={{sfnref|Lindgren & Wilde 2003}}}}
{{Cite book |last1=Kelaidis |first1=Gwen |date=2003 |chapter=The Xeric Rock Garden: An Intermountain Style |editor-last1=McGary |editor-first1=Mary Jane |title=Rock Garden Design and Construction |url=https://archive.org/details/rockgardendesign00nort/page/247 |url-access=registration |language=en |location=Portland, Oregon |publisher=Timber Press |isbn=978-0-88192-583-8 |oclc=50767902 |access-date=12 February 2025}}
{{Cite book |last1=Nelson |first1=Ruth Ashton |last2=Williams |first2=Roger Lawrence |date=1992 |title=Handbook of Rocky Mountain Plants |url=https://archive.org/details/handbookofrockym0000nels/page/305 |url-access=registration |language=en |edition=Fourth |location=Niwot, Colorado |publisher=Roberts Rinehart Publishers |isbn=978-0-911797-96-1 |oclc=26794859 |access-date=12 February 2025}}
{{Cite book |last1=Taylor |first1=Ronald J. |date=1992 |title=Sagebrush Country : A Wildflower Sanctuary |language=en |edition=revised |location=Missoula, Montana |publisher=Mountain Press Publishing Company |isbn=978-0-87842-280-7 |oclc=25708726}}

;Journals

{{cite journal |last1=Broderick |first1=Shaun R. |last2=Stevens |first2=Mikel R. |last3=Geary |first3=Brad |last4=Love |first4=Stephen L. |last5=Jellen |first5=Eric N. |last6=Dockter |first6=Rhyan B. |last7=Daley |first7=Shawna L. |last8=Lindgren |first8=Dale T. |date=February 2011 |title=A survey of Penstemon's genome size |journal=Genome |language=en |volume=54 |issue=2 |pages=160–173 |doi=10.1139/G10-106 |ref={{sfnref|Broderick et al. 2011}}}}
{{cite journal |last1=Keck |first1=David D. |author-link1=David D. Keck |date=June 1937 |title=Studies in Penstemon IV. The Section Ericopsis |journal=Bulletin of the Torrey Botanical Club |language=en |volume=64 |issue=6 |pages=357–381 |doi=10.2307/2481121 |issn=0040-9618 |jstor=2481121}}
{{cite journal |last1=Love |first1=Stephen L .|last2=Akins |first2=Candace J. |date=2020 |title=Fifth summary of the native seed germination studies of Norman C. Deno: species with names beginning with letters P and Q |journal=Native Plants Journal |language=en |volume=21 |issue=1 |pages=83–111 |doi=10.3368/npj.21.1.83 |issn=1522-8339}}
{{cite journal |last1=Tepedino |first1=V. J. |last2=Stanton |first2=N. L. |date=1980 |title=Spatiotemporal Variation in Phenology and Abundance of Floral Resources on Shortgrass Prairie |url=https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2396&context=gbn |journal=The Great Basin Naturalist |language=en |volume=40 |issue=3 |pages=197–215 |issn=0017-3614 |jstor=41711886 |url-status=live |archive-url=https://web.archive.org/web/20240422190436/https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2396&context=gbn |archive-date=22 April 2024 |access-date=14 February 2025}}
{{cite journal |last1=Wessinger |first1=Carolyn A. |last2=Freeman |first2=Craig C. |last3=Mort |first3=Mark E. |last4=Rausher |first4=Mark D. |last5=Hileman |first5=Lena C. |date=May 2016 |title=Multiplexed shotgun genotyping resolves species relationships within the North American genus Penstemon |journal=American Journal of Botany |language=en |volume=103 |issue=5 |pages=912–922 |doi=10.3732/ajb.1500519 |doi-access=free |issn=1537-2197 |pmc=10874106 |pmid=27208359 |ref={{sfnref|Wessinger et al. 2016}}}}

;Reports

{{cite report |last1=Heidel |first1=Bonnie |last2=Handley |first2=Joy |date=29 January 2007 |title=Penstemon laricifolius Hook. & Arn. ssp. exilifolius (A. Nels.) D.D. Keck (larchleaf beardtongue): a technical conservation assessment. |url=https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5206878.pdf |language=en |publisher=USDA Forest Service, Rocky Mountain Region |url-status=live |archive-url=https://web.archive.org/web/20250206020626/https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5206878.pdf |archive-date=6 February 2025 |access-date=16 February 2025}}

;Web sources

{{cite web |last1=Freeman |first1=Craig C. |date=29 July 2020 |orig-date=2019 |url=http://dev.floranorthamerica.org/Penstemon_laricifolius |title=Penstemon laricifolius |website=Flora of North America |page=138 |language=en |isbn=978-0190868512 |oclc=1101573420 |access-date=12 February 2025 |url-status=live |archive-url=https://web.archive.org/web/20250201230203/http://dev.floranorthamerica.org/Penstemon_laricifolius |archive-date=1 February 2025 |ref={{sfnref|Freeman 2020a}}}}
{{cite web |last1=Freeman |first1=Craig C. |date=29 July 2020 |orig-date=2019 |url=http://dev.floranorthamerica.org/Penstemon_laricifolius_var._exilifolius |title=Penstemon laricifolius var. exilifolius |website=Flora of North America |page=139 |language=en |isbn=978-0190868512 |oclc=1101573420 |access-date=12 February 2025 |url-status=live |archive-url=https://web.archive.org/web/20250201230439/http://dev.floranorthamerica.org/Penstemon_laricifolius_var._exilifolius |archive-date=1 February 2025 |ref={{sfnref|Freeman 2020b}}}}
{{cite web |last1=Freeman |first1=Craig C. |date=29 July 2020 |orig-date=2019 |url=http://dev.floranorthamerica.org/Penstemon_laricifolius_var._laricifolius |title=Penstemon laricifolius var. laricifolius |website=Flora of North America |page=139 |language=en |isbn=978-0190868512 |oclc=1101573420 |access-date=1 February 2025 |url-status=live |archive-url=https://web.archive.org/web/20250201230657/http://dev.floranorthamerica.org/Penstemon_laricifolius_var._laricifolius |archive-date=1 February 2025 |ref={{sfnref|Freeman 2020c}}}}
{{Cite NatureServe |date=31 January 2025 |id=2.151544 |title=Penstemon laricifolius |access-date=12 February 2025 |ref={{sfnref|NatureServe 2025a}}}}
{{Cite NatureServe |date=31 January 2025 |id=2.149610 |title=Penstemon laricifolius ssp. exilifolius |access-date=12 February 2025 |ref={{sfnref|NatureServe 2025b}}}}
{{cite usda plants|symbol=PELA9 |title=Penstemon laricifolius |date=1 February 2025 |ref={{sfnref|NRCS 2025}}}}
{{cite POWO |last1=POWO |date=2025 |id=808162-1 |title=Penstemon laricifolius Hook. & Arn. |access-date=12 February 2025 |ref={{sfnref|POWO 2025a}}}}
{{cite POWO |last1=POWO |date=2025 |id=187591-2 |title=Penstemon laricifolius var. exilifolius (A.Nelson) Payson |access-date=12 February 2025 |ref={{sfnref|POWO 2025b}}}}
{{cite POWO |last1=POWO |date=2025 |id=77226713-1 |title=Penstemon laricifolius var. laricifolius |access-date=12 February 2025 |ref={{sfnref|POWO 2025c}}}}