Penstemon sect. Petiolati

(Rydberg) Pennell

Contr. U.S. Natl. Herb. 20: 326, 328. 1920.

Basionym: Penstemon [unranked] Petiolati Rydberg Fl. Rocky Mts., 764. 1917
Treatment appears in FNA Volume 17. Treatment on page 228. Mentioned on page 93, 246.

Shrubs or subshrubs. Stems glabrous or scabrous to puberulent, glaucous. Leaves cauline, opposite, ± leathery or not, glabrate or scabrous, glaucous; cauline petiolate or sessile, blade ovate, margins toothed. Thyrses continuous, cylindric, axis puberulent, cymes 2 per node; peduncles and pedicels spreading to ascending. Flowers: calyx lobes: margins entire, narrowly scarious, glandular-pubescent, rarely glabrous; corolla magenta to pink, bilaterally symmetric, weakly bilabiate, not personate, weakly ventricose, glandular-pubescent externally, hairy internally abaxially, glandular-pubescent adaxially, throat moderately inflated, not constricted at orifice, rounded abaxially; stamens included or longer pair slightly exserted, filaments glabrous, pollen sacs opposite, subexplanate to explanate, dehiscing completely, connective splitting, sides glabrous, sutures smooth; staminode slightly exserted, flattened distally, 0.4–0.5 mm diam., tip straight, glabrous; style glabrous. Capsules glabrous. Seeds dark brown to black, angled, 0.9–1.2 mm.


w United States.


Species 1.

Penstemon petiolatus is the only member of sect. Petiolati. D. D. Keck (1937) noted morphologic similarities between P. petiolatus and P. clevelandii of sect. Spectabiles. Penstemon petiolatus has not been examined molecularly.

Selected References