Penstemon thurberi
Pacif. Railr. Rep. Parke, Bot., 15. 1856. (as Pentstemon)
Stems 20–40 cm, glabrous or glabrate. Leaves 10–20 pairs, 5–32 × 0.3–2 mm, blade base tapered, margins glabrous or scabrous, apex acuminate to mucronate. 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. 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. Capsules (4–)5–8 × 3–4 mm. 2n = 16.
Phenology: Flowering Apr–Aug(–Sep).
Habitat: Sandy or rocky slopes, chaparral, creosote shrublands, pine-juniper woodlands.
Elevation: 500–1200(–2100) m.
Distribution
Ariz., Calif., Nev., N.Mex., Tex., Utah, Mexico (Baja California, Chihuahua).
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.
Selected References
None.