Herbs, caulescent or essentially acaulescent (P. acaulis, P. yampaënsis). Stems retrorsely hairy, sometimes glandular-pubescent or glandular-villous distally or wholly, rarely glabrous, glabrate, or scabrous proximally or wholly, not glaucous. Leaves basal and cauline, sometimes ± cauline or ± basal, opposite, rarely whorled (P. albidus, P. auriberbis, P. jamesii), leathery or not, glabrous or glabrate, scabrous, retrorsely hairy, glandular-pubescent, pubescent, villous, or glandular-villous, not glaucous; basal and proximal cauline petiolate, sometimes sessile, rarely short-petiolate (P. pumilus); cauline sessile or short-petiolate, blade ovate, deltate-ovate, oblanceolate, lanceolate, elliptic, oblong, or linear, rarely pandurate, margins entire or toothed. Thyrses continuous or interrupted, cylindric, rarely ± secund to secund, axis glandular-pubescent, glandular-villous, or retrorsely hairy, rarely puberulent or glabrous, cymes 1 or 2 per node; peduncles and pedicels ascending to erect. Flowers: calyx lobes: margins entire, sometimes erose (P. atwoodii, P. laricifolius, P. triflorus), herbaceous or ± scarious, glandular-pubescent or glandular-villous, sometimes also scabrous, rarely entirely retrorsely hairy, puberulent, or glabrous; corolla white to lilac, lavender, blue, violet, purple, red, pink, or magenta, bilaterally symmetric, rarely nearly radially symmetric (P. goodrichii), weakly to strongly bilabiate, not personate, funnelform, tubular-funnelform, ventricose, or ampliate, glandular-pubescent externally, rarely glabrous (P. laricifolius), hairy internally abaxially, rarely glabrous or glandular-pubescent, throat gradually to abruptly inflated, rarely slightly inflated, constricted or not at orifice, rounded abaxially, sometimes slightly 2-ridged; stamens included, reaching orifice, or longer pair exserted, filaments glabrous, pollen sacs parallel to divergent or opposite, navicular to subexplanate or explanate, rarely navicular-sigmoid, dehiscing completely, rarely incompletely, proximal 1/5–1/2 indehiscent, connective splitting, rarely not, sides glabrous, sutures smooth or papillate; staminode included to exserted, flattened distally, 0.2–1.1 mm diam., tip straight to recurved or coiled, distal (40–)50–100% hairy, hairs to 4 mm; style glabrous, sometimes proximally glandular-pubescent (P. eriantherus). Capsules glabrous, rarely glandular-pubescent distally. Seeds brown, dark brown, or black, angled to reniform or slightly rounded, 1.5–4.8 mm.

Distribution

w North America, n Mexico.

Discussion

Species 31 (31 in the flora).

Members of sect. Cristati are mostly calciphiles on soils derived from limestone, dolomite, or other calcareous substrates. Species in sect. Cristati generally have hairy herbage, glandular-pubescent inflorescences and flowers, and staminodes prominently bearded more than half their lengths. Two species often assigned elsewhere (Penstemon acaulis, P. laricifolius) are included in this section based on molecular data (A. D. Wolfe et al. 2006). D. D. Keck’s (1938) sect. Aurator, which appears widely in the literature, is invalid, published without a Latin diagnosis.

Selected References

Keck, D. D. 1938. Studies in Penstemon VI. The section Aurator. Bull. Torrey Bot. Club 65: 233–255.

Lower Taxa

Penstemon acaulis, Penstemon albidus, Penstemon atwoodii, Penstemon auriberbis, Penstemon barnebyi, Penstemon breviculus, Penstemon calcareus, Penstemon cobaea, Penstemon concinnus, Penstemon distans, Penstemon dolius, Penstemon duchesnensis, Penstemon eriantherus, Penstemon franklinii, Penstemon goodrichii, Penstemon gormanii, Penstemon grahamii, Penstemon guadalupensis, Penstemon jamesii, Penstemon janishiae, Penstemon laricifolius, Penstemon marcusii, Penstemon miser, Penstemon moffatii, Penstemon monoensis, Penstemon nanus, Penstemon ophianthus, Penstemon pinorum, Penstemon pumilus, Penstemon triflorus, Penstemon yampaënsis

Key

1	Stems to 1 cm.	> 2
2	Basal and proximal cauline leaves 6–15(–22) × 0.6–1.3(–1.5) mm, blades linear.	Penstemon acaulis
2	Basal and proximal cauline leaves 15–25(–35) × 1.5–2.6(–4.5) mm, blades oblanceolate to linear.	Penstemon yampaënsis
1	Stems 2–65(–100) cm.	> 3
3	Corollas glabrous externally; calyx lobes glabrous.	Penstemon laricifolius
3	Corollas glandular-pubescent externally; calyx lobes hairy.	> 4
4	Pollen sacs parallel, navicular.	> 5
5	Staminodes prominently exserted; basal and proximal cauline leaf margins sharply serrate-dentate, rarely entire; corollas ventricose.	Penstemon pinorum
5	Staminodes included to barely exserted; basal and proximal cauline leaf margins entire or ± dentate; corollas funnelform or tubular-funnelform.	> 6
6	Thyrses 8–30 cm, interrupted; stems (25–)30–60 cm; Arizona.	Penstemon distans
6	Thyrses 2–7(–8) cm, continuous or interrupted; stems 2–25 cm; Utah.	> 7
7	Leaves glabrous abaxially, retrorsely hairy adaxially, usually only along midveins on distal caulines; pollen sacs 1.3–1.6 mm.	Penstemon franklinii
7	Leaves densely retrorsely hairy; pollen sacs 1.7–2 mm.	Penstemon nanus
4	Pollen sacs opposite or divergent, explanate or subexplanate to navicular or navicular-sigmoid.	> 8
8	Thyrse axes puberulent or retrorsely hairy.	> 9
9	Leaves: basal and proximal cauline blades oblanceolate to linear, 1–4 mm wide, caulines usually arcuate; Idaho.	Penstemon pumilus
9	Leaves: basal and proximal cauline blades spatulate to oblanceolate, 2–14 mm wide, caulines not arcuate; Nevada, Utah.	> 10
10	Cauline leaves 12–38 × 3–7 mm; stems 2–14(–20) cm, prostrate, decumbent, ascending, or erect; corollas with, rarely without, faint blue or reddish purple nectar guides; ec Nevada, wc Utah.	Penstemon dolius
10	Cauline leaves 14–23 × 1–4 mm; stems 2–6(–8) cm, ascending to erect; corollas without nectar guides; ne Utah.	Penstemon duchesnensis
8	Thyrse axes glandular-pubescent or glandular-villous, sometimes retrorsely hairy.	> 11
11	Capsules sparsely glandular-pubescent distally; styles sparsely glandular-pubescent proximally or glabrous.	Penstemon eriantherus
11	Capsules glabrous; styles glabrous.	> 12
12	Pollen sacs navicular or navicular-sigmoid.	> 13
13	Corollas ventricose, 19–30 mm; staminodes prominently exserted.	Penstemon gormanii
13	Corollas tubular-funnelform, 10–22(–24) mm; staminodes included to exserted.	> 14
14	Stems puberulent, hairs usually white, scalelike; leaves densely retrorsely hairy, hairs white, scalelike; California.	Penstemon monoensis
14	Stems glabrous or retrorsely hairy, sometimes sparsely glandular-pubescent distally, hairs not white or scalelike; leaves glabrous, puberulent, or retrorsely hairy, hairs not white or scalelike; Colorado, New Mexico, Utah.	> 15
15	Pollen sacs divergent, dehiscing incompletely; corollas weakly bilabiate; Colorado, New Mexico.	Penstemon auriberbis
15	Pollen sacs opposite, dehiscing completely; corollas bilabiate; Colorado, Utah.	> 16
16	Basal and proximal cauline leaf blades oblanceolate to lanceolate; corollas 10–13 mm; styles 6–8 mm; Utah.	Penstemon atwoodii
16	Basal and proximal cauline leaf blades spatulate to oblanceolate or ovate; corollas 15–20(–22) mm; styles 10–12 mm; Colorado, Utah.	Penstemon moffatii
12	Pollen sacs explanate, rarely subexplanate.	> 17
17	Corollas tubular-funnelform to funnelform.	> 18
18	Corollas white, sometimes tinged pink or lavender.	> 19
19	Leaves glabrate or puberulent to scabrous, basals and proximals (4–)7–18(–20) mm wide, blades oblanceolate or obovate to lanceolate; thyrse axes densely glandular-pubescent; Alberta, Manitoba, Ontario, Saskatchewan, Colorado, Iowa, Kansas, Minnesota, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Wyoming.	Penstemon albidus
19	Leaves glabrous or glabrate, rarely basals retrorsely hairy along midveins, basals and proximals 1–6 mm wide, blades linear, rarely lanceolate; thyrse axes glandular-pubescent; Texas.	Penstemon guadalupensis
18	Corollas blue, bluish lavender, lavender, pink, rose red, rose purple, violet, or purple.	> 20
20	Corollas pink to rose red or rose purple; California, sw Nevada.	Penstemon calcareus
20	Corollas lavender, violet, purple, bluish lavender, or blue; e Nevada, Utah.	> 21
21	Staminodes exserted; corollas bilabiate, tubular-funnelform.	Penstemon concinnus
21	Staminodes included; corollas weakly bilabiate, funnelform.	> 22
22	Stems glabrous or slightly retrorsely hairy proximally, glandular-pubescent distally; basal and proximal cauline leaf blades lanceolate to linear; staminodes: distal 5–7 mm densely pilose, hairs yellow, to 0.8 mm.	Penstemon goodrichii
22	Stems retrorsely hairy; basal and proximal cauline leaf blades oblanceolate to lanceolate; staminodes: distal 3–5 mm sparsely to densely pubescent, hairs yellow, to 1 mm.	Penstemon marcusii
17	Corollas ventricose, ventricose-ampliate, or ampliate.	> 23
23	Corollas 35–55 mm; staminodes 23–30 mm; styles 18–34 mm.	Penstemon cobaea
23	Corollas 10–35 mm; staminodes 7–20 mm; styles 7–24 mm.	> 24
24	Corollas glandular-pubescent internally abaxially, sometimes also pilose.	> 25
25	Corollas 14–20(–22) mm; styles 11–13 mm; capsules 6–11 mm.	Penstemon ophianthus
25	Corollas 22–35 mm; styles 17–24 mm; capsules (7–)10–16 mm.	> 26
26	Staminodes exserted, distal 10–14 mm lanate, hairs to 3.5 mm; corolla throats abruptly inflated.	Penstemon jamesii
26	Staminodes included or reaching orifice, distal 8–12 mm sparsely to moderately pilose, hairs to 1 mm; corolla throats gradually inflated.	Penstemon triflorus
24	Corollas lanate or villous internally abaxially.	> 27
27	Styles 15–24 mm; corollas 18–35 mm, tubes (6–)8–13 mm; staminodes 16–20 mm.	> 28
28	Corollas 28–35 mm, ventricose-ampliate, sparsely white-lanate internally abaxially; Colorado, Utah.	Penstemon grahamii
28	Corollas 18–28 mm, ventricose, densely white-lanate internally abaxially; California, Idaho, Nevada, Oregon.	Penstemon janishiae
27	Styles 7–11 mm; corollas 10–22 mm, tubes 4–7 mm; staminodes 7–10 mm.	> 29
29	Staminodes reaching orifices or exserted; corollas ampliate; leaves retrorsely hairy, sometimes glabrate; Arizona, Colorado, New Mexico, Utah.	Penstemon breviculus
29	Staminodes exserted or prominently exserted; corollas ventricose; leaves retrorsely hairy, glabrate, or glabrous; California, Idaho, Nevada, Oregon.	> 30
30	Corollas 10–14 mm; styles 7–9 mm; capsules 3–6 mm; California, Nevada.	Penstemon barnebyi
30	Corollas 14–22 mm; styles 9–10 mm; capsules (6–)8–11 mm; Idaho, Oregon.	Penstemon miser