Cirsium (thistles) have long been considered one of the most taxonomically challenging groups of plants in western North America. However, the relationships among thistles have become clearer thanks to recent molecular phylogenetic work. The results of this work revealed that Cirsium eatonii var. eriocephalum was polyphyletic, consisting of three distinct evolutionary lineages. Each of these lineages was also found to be distinct morphologically as well as geographically. Multiple lines of evidence thus indicated that Cirsium eatonii var. eriocephalum consisted of at least three distinct species. The first species recognized was the previously named C. scopulorum. The second lineage was recently named and described as Cirsium funkiae. The third lineage is here described as a new species, Cirsium tukuhnikivatzicum. Mount Tukuhnikivatz is a prominent backdrop against this new species of thistle. Tukuhnikivatz is also the Southern Paiute word for “place where the sun shines longest” and Ute word for “where the sun sets last.” The specific epithet tukuhnikivatzicum is therefore used to indicate the distribution of this species, while also acknowledging and paying tribute to the Southern Paiute and Ute legacy of use of the La Sal Mountains. There was a taxonomic lag time of 112 yr between the first specimen collection and the new species description presented here.
It has been estimated that of the “missing” plant species remaining to be identified and described, approximately half have already been collected and are currently stored in herbaria (Bebber et al. 2010). This creates a taxonomic lag time, or time from collection to new species discovery. Sometimes, the taxonomic lag between collection and description is the result of species that are not well-represented morphologically by herbarium specimens. These species often lose color upon drying, are too big to fit on an herbarium sheet and are thus cut to size, or are fragments of the entire plant. Therefore, the true morphology of the plant is often lost. This not only leads to incorrect determinations, but hinders the discovery of new species.
Cirsium Mill. (“thistles”) is comprised of approximately 100 species distributed across North America (Keil 2006). Within Cirsium, one of the most difficult species to delimit has been the morphologically polymorphic C. eatonii B.L.Rob. (“mountaintop thistle”) varietal complex. This complex was treated as seven varieties by Keil (2006) in a treatment for Flora of North America: C. eatonii var. clokeyi (S.F.Blake) D.J.Keil, C. eatonii var. eatonii, C. eatonii var. eriocephalum (A.Gray) D.J.Keil, C. eatonii var. hesperium (Eastw.) D.J.Keil, C. eatonii var. murdockii S.L.Welsh, C. eatonii var. peckii (L.F.Hend.) D.J.Keil, and C. eatonii var. viperinum D.J.Keil. The common name “mountaintop thistle” was derived from the distribution of these varieties on mountaintops throughout the southern Rocky Mountains and adjacent Inter-mountain Region. These taxa were included as varieties within Cirsium eatonii primarily based on this shared distribution on mountaintops as well as some overlapping morphological features (Table 1).
Molecular phylogenetic inference to test the monophyly of this varietal complex demonstrated that C. eatonii, as circumscribed by Keil (2006), was polyphyletic (Ackerfield et al. 2020). To resolve this polyphyly, varieties within the C. eatonii complex were separated out as distinct species (Ackerfield et al. 2020, 2022; Siniscalchi et al. 2023). The previously described species C. clokeyi S.F.Blake, C. murdockii (S.L.Welsh) Cronquist, C. peckii L.F.Hend., and C. tweedyi (Rydb.) Petr. were reinstated, and two new combinations were made: C. harrisonii (S.L.Welsh) Ackerf. & D.J.Keil and C. viperinum (D.J.Keil) Ackerf. & D.J.Keil (Table 1).
However, not only was C. eatonii resolved as polyphyletic, but C. eatonii variety eriocephalum was resolved as polyphyletic as well (Ackerfield et al. 2020). Cirsium eatonii variety eriocephalum was delimited from the other varieties in the C. eatonii complex by the presence of densely woolly involucral bracts and heads in a nodding array (Keil 2006). Three unique evolutionary lineages were recovered for C. eatonii variety eriocephalum, each corresponding to a distinct morphology: 1) white, pale pink, or pale purple style branches with heads in a nodding cluster, now recognized as Cirsium scopulorum (Greene) Cockerell, 2) yellow style branches with heads in a nodding cluster, now recognized as the newly described Cirsium funkiae Ackerf. (Ackerfield 2022), and 3) pink style branches with heads in openly paniculiform arrays or sometimes in racemiform arrays, now recognized as the new species described here, Cirsium tukuhnikivatzicum Ackerf., sp. nov. (Fig. 1; Table 1). In addition to exhibiting a unique morphology, each lineage also exhibits a distinct geographic range (Fig. 2). Cirsium tukuhnikivatzicum is endemic to the La Sal Mountains of Utah and well separated from the distributions of C. funkiae and C. scopulorum. Therefore, the common name of La Sal thistle is recommended for this species. Mount Tukuhnikivatz is one of 12 mountain tops in the La Sal Mountains and is a prominent backdrop for the La Sal thistle. Additionally, C. tukuhnikivatzicum is found along the trail to the top of Mount Tukuhnikivatz. Tukuhnikivatz is the Southern Paiute word for “place where the sun shines longest” and Ute word for “place where the sun sets last.” The specific epithet tukuhnikivatzicum also acknowledges and pays tribute to the Southern Paiute and Ute legacy of use of the La Sal Mountains.
Materials and Methods
Examination of Specimens—Herbarium loans were obtained from BRY and RM. Additionally, herbarium specimens from ASC, COLO, HU, NY, UT, and UTC were viewed online through the SEINet portal ( http://swbiodiversity.org). Herbarium acronyms follow those in Index Herbariorum (Thiers 2022). The author also visited the La Sal Mountains to make type collections and observations of the plants in the field. Specimens were collected under USDA Forest Service permit number FS-2400–008 made to the author. Taxonomic measurements were taken in metric units from pressed herbarium specimens. iNaturalist ( http://www.inaturalist.org) observations were used to further document the corolla and style tip color, which fades on herbarium specimens.
Table 1.
Morphological characteristics for species formally included in the C. eatonii varietal complex.
Species Delimitation—Species delimitation was performed based on morphology and phylogenetic inference. The general lineage species concept (De Queiroz 2007) was used, which defines a species as a unique evolutionary lineage. This concept was used in conjunction with the phylogenetic species concept (Nixon and Wheeler 1990) in which a species is the smallest system of related populations with a uniquely diagnosable set of morphological character states.
Results and Discussion
The first specimen of the La Sal thistle was collected by Per Axel Rydberg & Albert Garrett in 1911 (USA Utah: Western slope of La Sal mountains, 6 Jul 1911, Rydberg & Garrett 8612 (NY); Fig. 3). This specimen was later identified as Cirsium scopulorum by Rydberg, and thus began the incorrect usage of this binomial for this species. In 1963, thistle researcher Raymond J. Moore (Canada Department of Agriculture) sent a fragment of the La Sal thistle consisting of a single head and leaf to Arthur Cronquist, curator at the New York Botanical Garden and a leading expert on the Asteraceae family (USA Utah: Grand Co.: Spruce-pine forest in the LaSal Mts., 2 Aug 1963, Gillett & Mosquin 12353 (NY); Fig. 3). Moore wrote a letter stating “herewith in [is] a piece of the strange Cirsium that I was trying to match with specimens at NY … our plant is 10 dm tall, a single stout woody, brown, ribbed stem, piloselong shaggy hairs, more or less parallel to stem … approx. 40 heads per plant. Leaves numerous, ascending, stiff, to 80 cm long, base clasping, short-decurrent” (Fig. 3). Cronquist replied to Moore, stating “So far as the head and leaf you sent me are concerned, they are, at least at first sight, very much like the general run of material in our folder of C. scopulorum (e.g., Rydberg & Garrett 8612, La Sal Mts., Utah).” However, Cronquist also stated “If your plant represents a considerable population, one might begin to think of the possibility that it belongs to an undescribed species … In the present state of knowledge (or lack of knowledge) of Cirsium, this is as far as I can go.” And with that, the new species was left undescribed for the next 60 yr. All in all, there was a taxonomic lag time of 112 yr from the first collection made in 1911 to the recognition of the La Sal thistle as a new species.
Once identified as a new species, iNaturalist observations and herbarium specimens were used to quantify the La Sal thistle's unique morphology and geographic range. It was especially useful to use iNaturalist observations in conjunction with herbarium specimens, as the overall morphology of this species is often better represented through a photograph than pressed specimens. The flowers of Cirsium often fade to brown shortly after collecting, and thus coloration is usually not discernable from herbarium specimens. Additionally, these plants reach heights of over 10 dm, which is not well represented on an herbarium specimen.
Although considered one of the “mountaintop thistles” by Keil (2006), Cirsium tukuhnikivatzicum is mostly found below tree line in montane meadows. However, there is one thistle specimen that was collected in the alpine of the La Sal Mountains that has yet to be conclusively determined to species (USA Utah: San Juan Co.: Second major saddle on crest of range S of Mt. Mellenthin, ca 19 mi SE of Moab, 12,000 ft., 28 Jul 1984, J Tuhy 1849 (BYU). This specimen most closely resembles Cirsium hesperium (Eastw.) Rydb. with an erect array of densely clustered heads with woolly tomentose involucral bracts. There are no known photographs of this population in flower to use as a comparison, and just this single herbarium specimen. There are three possibilities for this specimen: 1) it represents a high alpine form of C. tukuhnikivatzicum, 2) it is a disjunct population of C. hesperium, or 3) it is an undescribed species. Additional work is needed to determine which of the possibilities best fits this specimen.
Taxonomic Treatment
Cirsium tukuhnikivatzicum Ackerf., sp. nov. Type: USA. Utah: San Juan Co.: Manti-La Sal National Forest, meadow adjacent to Medicine Lakes, approximately 0.5 miles S of La Sal Pass off of La Sal Pass Rd., 9980 ft., 8 Aug 2021, J Ackerfield 8007 (holotype: KHD!, isotypes: BRY!, COLO!, RM!, UT!).
Perennial, caulescent herbs. Stems usually solitary, deep maroon, erect, 3.8–21 dm tall, simple or sometimes branched above the middle, thinly arachnoid. Leaves oblong to narrowly elliptic or oval, the lower leaves pinnatifid with 7–13 pairs of lobes, 11.5–21 cm long and 3.5–6.3 cm wide (including lobes), midribs 4–8 mm wide, lobes 1.5–3 cm long and spaced 3–12 mm apart, main spines 1.5–4 mm long, the upper leaves pinnatifid with 5–7 pairs of lobes, 6–9.5 cm long and 1.8–3.5 cm wide (including lobes), midribs 4–5 mm wide, lobes 0.3–2 cm long and spaced 2–11 mm apart, main spines 4–10 mm long, adaxial surfaces glabrous to sparsely pubescent, abaxial surfaces tomentose, cauline leaves well-distributed, sessile or clasping to decurrent on the stem 3–10 mm. Heads 6–55, sessile or on peduncles 3–30 mm long, in openly paniculiform arrays, sometimes in racemiform arrays, borne singly or in clusters of 2–3 at tips of peduncles, or with heads arising from leaf axils in the proximal 3/4 of the stem. Involucres green, hemispheric to campanulate, 1.2–2.2 ｘ 1.7–3.2 cm, thinly to densely tomentose, phyllaries connected by long septate or non-septate trichomes. Involucral bracts in 5–6 series, subequal, with entire margins, tapering to spines 7–15 mm long, abaxial faces without glutinous ridge, lower and middle phyllaries with spreading tips, upper phyllaries with spine tips spreading to deflexed. Corollas white to light pink, 18–22 mm long, tubes 6–9 mm long, throats 4–9 mm long, lobes 4–8 mm long. Anther tubes white with pink or purple stripes, 6.5–9 mm long. Style branches pink to purple, 3–5 mm long, exserted beyond the corolla lobes. Cypselae light to dark brown with grayish mottling, 6–7.5 mm long. Pappi 12–20 mm long. Figures 4, 5.
Phenology—This species flowers from late July to late August, and fruits from mid-August to early September.
Distribution and Habitat—This species is endemic to the La Sal Mountains or La Sal Range (Fig. 2). The La Sal Mountains are found in eastern Utah, located in Grand and San Juan counties near the border of Colorado. This species occurs in high elevation montane meadows surrounded by spruce-fir forest. It is occasionally found above tree line in the alpine tundra.
Associates—This species occurs principally in open, montane meadows with Achillea millefolium L., Fragaria vesca L., Potentilla pulcherrima Lehm., Pseudocymopterus montanus (A.Gray) J.M.Coult. & Rose, Taraxacum officinale G.H.Weber ex Wiggers, and Valeriana edulis Nutt. ex Torr. & A.Gray. Above tree line, this species occurs on rocky slopes with Erigeron speciosus (Lindl.) DC., Heliomeris multiflora Nutt., Monardella odoratissima Benth., Taraxacum officinale, and Trisetum spicatum (L.) K.Richt. Interestingly, the first specimen of this species collected by Rydberg and Garrett also contains leaf fragments of Potentilla pulcherrima (Fig. 3), indicating that this specimen was collected in the same habitat as C. tukuhnikivatzicum.
Conservation—The La Sal thistle occurs primarily on federally-owned land, including within the Mt. Peale Research Natural Area. Sheer abundance and distribution within the Mt. Peale Research Natural Area offer the species some degree of protection, and currently, populations appear to be stable. However, the author noted several plants that had been deliberately pulled or trampled along the trail to Mount Tukuhnikivatz. A common misconception that all thistles are invasive plants leads some people to try to mitigate for these “weeds.” The placement of a sign at the trailhead to Mount Tukuhnikivatz educating the public about this native, narrowly endemic thistle could help reduce human interference with the plants. The limited range of the La Sal thistle also makes it potentially highly vulnerable to habitat loss or even extirpation due to climate change or other stochastic factors. Additionally, the recent introduction of mountain goats to the La Sal Mountains could impact this narrowly endemic thistle. Further monitoring of the La Sal thistle populations would be beneficial to determine if mountain goats or climate change are negatively impacting the species.
Etymology—Cirsium tukuhnikivatzicum is named for Mount Tukuhnikivatz, one of three mountain peaks that occurs near this species and one of 12 peaks that form the La Sal Mountains. Tukuhnikivatz is also the Southern Paiute word for “place where the sun shines longest” and Ute word for “place where the sun sets last.” The specific epithet tukuhnikivatzicum therefore acknowledges and pays tribute to the Southern Paiute and Ute legacy of use of the La Sal Mountains.
Notes—This species is most similar morphologically to C. inamoenum (Greene) D.J.Keil, as both species exhibit involucral bracts that are tomentose and mostly spreading at right angles to the head. However, C. inamoenum has mid-stem leaves with bases long-decurrent 1–3 cm as spiny wings, with most bases decurrent over 2 cm, and heads in open, corymbiform arrays. Alternatively, C. tukuhnikivatzicum has mid-stem leaves that are sessile to shortly decurrent 0.3–1 cm, and heads in openly paniculiform or sometimes racemiform arrays.
Additional Specimens Examined—USA. —UTAH: San Juan Co. La Sal Pass, end of USFS Rd. #725, 18 Aug 2016, M Licher 5417 (ASC); San Juan Co. La Sal Pass, 28 Aug 1984, B Franklin 1334 (BRY); San Juan Co. SE slope LaSal Mts, 26 Jul 1986, B Franklin 4041 (BRY); San Juan Co. Meadows at edge of spruce forest on the west slope of the La Sal Mts ca 4 km by road west of Geyser Pass, 5 Sep 1987, A Cronquist 12072 (BRY); San Juan Co. Hell Canyon S of road below old mine site on the LaSal Mts, 19 Jul 1988, S Richardson 32 (BRY); San Juan Co. Manti-La Sal Nat. Forest, La Sal Mts., S slope of Mt. Tukuhnikivatz, 28 Jul 1982, V Siplivinsky & H Beck 4441 (COLO); Grand Co. La Sal Mts, 24 Jul 1924, E Payson & L Payson 4026 (GH); Grand Co. Mt. Peale RNA, La Sal mountains, Saddle just S of Mt. Laurel, 23 km SE Moab, 6 Aug 2009, J Fowler 6425 (RM).
Fig. 4.
Cirsium tukuhnikivatzicum Ackerf. A. Habitat and habit. B. Habit. C. Close-up of heads. D. Close-up of head and involucral bracts. E. Disk flower. F. Cypselae. G. Leaf. Photos taken by Jennifer Ackerfield.
Fig. 5.
Cirsium tukuhnikivatzicum Ackerf. color illustration. A. Habit. B. Head. C. Mature head split in half to show the placement of the seeds on the receptacle. D. Disk flower. E. Anther tube dehisced lengthwise. F. Cypselae. G. Cypselae with pappus. Illustration by Shiere Melin, Denver Botanic Gardens.
Key to the Native Thistles of Utah
Recently described new species and nomenclatural changes for the thistles of Utah has necessitated a key to all currently recognized native thistle species in the state, following the nomenclature proposed in Ackerfield et al. (2020). In this key, Cirsium virginense S.L.Welsh is considered synonymous with C. mohavense (Greene) Petr. based on additional genetic work (Siniscalchi et al. 2023) and further examination of specimens by the author.
Ackerfield et al. (2020) hypothesized that specimens from Cedar Breaks in Dixie National Forest should be recognized as Cirsium markaguntense (S.L.Welsh) Ackerf. & D.J.Keil. However, additional genetic work (Siniscalchi et al. 2023) does not support this hypothesis. Therefore, specimens from this population are here recognized as C. clavatum (M.E.Jones) Petr. Cirsium clavatum from Cedar Breaks may hybridize with C. wheeleri Petr., as C. clavatum from this area appears intermediate between these two species. Additional work on Cirsium in this area is necessary. Cirsium parryi Petr. is excluded from this key, as examination of specimens revealed that these specimens were misidentifications of C. pulchellum Wooton & Standl. Cirsium centaureae (Rydb.) K.Schum. is also excluded, as examination of specimens revealed that these were misidentifications of C. clavatum.
1. Plants acaulescent with no true stem; heads clustered at ground level; mountain meadows, scattered across the state C. americanum (A.Gray) K.Schum.
1. Plants with a conspicuous leafy stem; heads elevated on a stem 2
2. Corolla lobes at least twice as long as the corolla throat; involucres cylindric to campanulate 3
3. Corollas red or reddish-pink; deserts, rocky cliffs, widespread C. arizonicum (A.Gray) Petr.
3. Corollas purple or pinkish-purple 4
4. Style tips 2–4.5 mm long; corolla lobes 8–15 mm long; canyons and cliff walls, widespread C. pulchellum Wooton & Standl.
4. Style tips 1.2–3 mm long; corolla lobes 13–18 mm long; canyons and cliffs, southern Utah C. calcareum (M.E.Jones) Wooton & Standl.
2. Corolla lobes less than twice as long as the corolla throat; involucres hemispheric, ovoid, or campanulate 5
5. Leaves glabrous on both sides, or nearly so 6
6. Leaves 6–40 cm wide, the lobes not extending more than halfway to the center midrib, the bases mostly auriculate clasping or sometimes just the upper leaves decurrent to 2 cm on the stem; outer involucral bracts entire 7
7. Involucres 1.4–2 ｘ 1–2 cm; corollas 16–20 mm long; leaves strongly undulate; known from hanging gardens along the Colorado River drainage, not known from Zion National Park C. rydbergii Petr.
7. Involucres 2.5–4 ｘ 2.5–3.5 cm; corollas 20–26 mm long; leaves usually not strongly undulate; known from hanging gardens in Zion National Park C. joannae S.L.Welsh, N.D.Atwood & L.C.Higgins
6. Leaves 1–7 cm wide, the lobes extending more than halfway to the center midrib, the bases usually decurrent as spiny wings 1–3 cm long; outer involucral bracts pinnately spinose 8
8. Involucral bracts suffused with dark purple; alpine of the Tushar Mountains C. harrisonii (S.L.Welsh) Ackerf. & D.J.Keil
8. Involucral bracts mostly green or sometimes purplish-tinged but not suffused with dark purple; plants not of the Tushar Mountains 9
9. Spines on leaves lax and soft; leaf lobes linear to linear-lanceolate; plants of hanging gardens, ledges, and seeps in juniper and sagebrush communities below 1900 m in elevation C. ownbeyi S.L.Welsh
9. Spines on leaves stiff and sharp; leaf lobes broadly triangular to lanceolate; plants of the montane to alpine above 1900 m in elevation. 10
10. Involucral bracts densely tomentose; alpine in the eastern portion of the Uinta Mts C. murdockii (S.L.Welsh) Cronquist
10. Involucral bracts glabrous or sparsely pubescent 11
11. Corollas purple or pinkish-purple; leaves conspicuously undulate; alpine in the western portion of the Uinta Mts, Stansbury Mts., and Deep Creek Range C. eatonii B.L.Rob.
11. Corollas white or sometimes pale pink, rarely deep pink; leaves flat or slightly undulate; mountain meadows, scattered across the state C. clavatum (M.E.Jones) Petr.
5. Leaves pubescent at least below (usually tomentose abaxially, glabrate above) 12
12. Mid-stem leaves with bases long-decurrent 1–5 cm (at least some over 1 cm) as spiny wings 13
13. Mid-stem leaves usually spinose-toothed or shallowly lobed; leaves more or less gray-tomentose above and below; found near desert seeps and springs, known from near St. George along the Virgin River (Washington Co.) C. mohavense (Greene) Petr.
13. Mid-stem leaves deeply lobed, the lobes extending over halfway to the midrib; leaves white- to gray-tomentose below and green above; found in pinyon-juniper and desert shrub communities, not known from Washington Co 14
14. Involucral bracts tomentose, the lower bracts spreading at right angles to the head from near the midpoint of the bract; heads usually larger, 1.5–5 cm wide; open slopes, mountain meadows, scattered across the state C. inamoenum (Greene) D.J.Keil
14. Involucral bracts glabrate or tomentose on the margins, the lower bracts ascending or just the spine tips spreading at right angles to the head; heads usually smaller, 1–2 cm wide 15
15. Leaves green above, mostly with 5–8 pairs of lobes; known from Cache Co C. pulcherrimum (Rydb.) K.Schum.
15. Leaves densely white- to gray-tomentose on both sides (rarely green above), mostly with 8–15 pairs of lobes; plants of white shale outcrops of the Green River Formation in the Uinta Basin C. barnebyi S.L.Welsh & Neese
12. Mid-stem leaves with bases sessile to clasping or short-decurrent to 1 cm 16
16. Outer involucral bracts pinnately spinose along the margins; mountain meadows, scattered across the state C. clavatum (M.E.Jones) Petr.
16. Outer involucral bracts entire 17
17. Involucral bracts with a conspicuous, white (when fresh, drying brown) glutinous dorsal ridge 18
18. Middle and lower involucral bracts bent in the middle (the spreading portion including the spine tip and part of the involucral bract); heads solitary, usually on long, naked peduncles; plants usually flowering in April and May; deserts, widespread C. neomexicanum A.Gray
18. Middle and lower involucral bracts not bent in the middle; heads various; plants usually flowering after May 19
19. Leaves flat or nearly so, with a narrow (ca. 5 mm wide) midrib, usually with a long, terminal lobe, lateral lobes short and well-separated, sometimes leaves all entire or very shallowly lobed; forests and meadows, widespread C. wheeleri Petr.
19. Leaves undulate, the basal leaves conspicuously so, never entire, the midrib usually wider (ca. 10 mm wide), lacking a long, terminal lobe, lateral lobes triangular to lanceolate, close together 20
20. Heads smaller, the involucre 18–30 mm high; involucral bracts in 3–4 (5) rows; deserts and roadsides, widespread C. tracyi Petr.
20. Heads larger, the involucre 25–50 mm high; involucral bracts in 5–7 rows; deserts, roadsides, and open slopes, widespread C. undulatum Spreng.
17. Involucral bracts lacking a conspicuous, white glutinous dorsal ridge 21
21. Involucral bracts thinly to densely tomentose, the lower and middle bracts spreading at right angles to the head from near the midpoint of the bract; heads in racemiform or paniculiform arrays, not closely subtended by bract-like leaves which overtop the heads; montane meadows and alpine slopes of the La Sal Mts C. tukuhnikivatzicum Ackerf.
21. Involucral bracts glabrous, appressed-ascending; heads usually tightly clustered in a dense, terminal subcapitate array or sometimes racemiform array, usually closely subtended by bract-like leaves which overtop the heads, these usually whitish at the base or sometimes tinged pink to purplish 22
22. Bract-like leaves subtending the heads fringed with weak spines; wet mountain meadows and along streams, scattered across the state C. scariosum Nutt.
22. Bract-like leaves subtending the heads fringed with stout, firm spines; wet meadows, salt marshes, along streams, and valley bottoms, scattered across the state C. coloradense (Rydb.) Cockerell ex Daniels
Acknowledgments
I would like to thank Marc Chase Coles-Ritchie, Jordan Ackerfield, and Lydia Jones for joining me to collect type specimens of C. tukuhnikivatzicum in the La Sal Mountains. I would also like to thank the Utah Native Plant Society for their support as this work was funded in part by a grant from the Society to the author. I would like to thank Lisa Eldred at Denver Botanic Gardens for facilitating the illustration process, and Shiere Melin at Denver Botanic Gardens for creating the beautiful illustration presented here.
© Copyright 2023 by the American Society of Plant Taxonomists
