Penstemon thurberi |
Penstemon sect. Ambigui |
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Thurber's beardtongue, Thurber's penstemon |
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Habit | Subshrubs. | |||||
Stems | 20–40 cm, glabrous or glabrate. |
glabrous, glabrate, or scabrous proximally, not glaucous. |
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Leaves | 10–20 pairs, 5–32 × 0.3–2 mm, blade base tapered, margins glabrous or scabrous, apex acuminate to mucronate. |
cauline, opposite, not leathery, glabrous or scabrous, not glaucous; cauline sessile, blade linear, margins entire. |
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Thyrses | 2–15(–23) cm, verticillasters (2–)5–10(–30), cymes 1- or 2-flowered; proximal bracts linear, 3–22 × 0.2–1 mm; peduncles and pedicels glabrous or scabrous. |
interrupted, cylindric to conic, axis glabrous or scabrous, cymes 2 per node; peduncles and pedicels spreading or ascending. |
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Flowers | calyx lobes ovate, 1–2.7 × 0.9–1.5 mm; corolla lavender to violet, lined internally abaxially with reddish purple nectar guides, funnelform, 8–14 mm, glandular-pubescent internally in 2 lines on abaxial surface, sometimes also in sinuses of adaxial lobes, tube (1.5–)2–3 mm, throat 3–5 mm diam.; stamens included or longer pair reaching orifice or barely exserted, pollen sacs 0.4–0.5 mm; staminode 5–6 mm; style 7–9 mm. |
calyx lobes: margins entire or erose, broadly scarious, glabrous; corolla pink or lavender to violet, bilaterally symmetric, bilabiate, not personate, salverform or funnelform, glabrous externally, glandular-pubescent internally abaxially, throat slightly inflated, not constricted at orifice, rounded abaxially; stamens included or longer pair reaching orifice or barely exserted, filaments glabrous, pollen sacs divergent, explanate, dehiscing completely, connective splitting, sides glabrous, sutures smooth; staminode included, terete or slightly flattened distally, 0.1 mm diam., tip straight, glabrous; style glabrous. |
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Capsules | (4–)5–8 × 3–4 mm. |
glabrous. |
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Seeds | dark brown to reddish brown, angled, 1–2.8 mm. |
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2n | = 16. |
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Penstemon thurberi |
Penstemon sect. Ambigui |
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Phenology | Flowering Apr–Aug(–Sep). | |||||
Habitat | Sandy or rocky slopes, chaparral, creosote shrublands, pine-juniper woodlands. | |||||
Elevation | 500–1200(–2100) m. (1600–3900(–6900) ft.) | |||||
Distribution |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Chihuahua)
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w United States; n Mexico |
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Discussion | Plants of Penstemon thurberi from northern Clark County, Nevada, with corollas 8–9 mm and capsules 4–5 mm have been treated as var. anestius. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 2 (2 in the flora). Section Ambigui includes two subshrubby species of the southwestern and south-central United States and northern Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 17, p. 95. | FNA vol. 17, p. 94. | ||||
Parent taxa | Plantaginaceae > Penstemon > subg. Penstemon > sect. Ambigui | Plantaginaceae > Penstemon > subg. Penstemon | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | P. thurberi var. anestius | P. | ||||
Name authority | Torrey: Pacif. Railr. Rep. Parke, Bot., 15. (1856) — (as Pentstemon) | (Rydberg) Pennell: Contr. U.S. Natl. Herb. 20: 326, 333. (1920) | ||||
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