Penstemon cobaea Nutt., . Perennial herb, not rosetted, several–stemmed at base, in range to 60 cm long; shoots with only cauline leaves, short–hairy with curved to straight hairs.
Stems cylindric, < 5 mm diameter, yellow–green tinged red–purple, densely short–hairy to puberulent.
Leaves opposite decussate, simple and sessile fused across node, without stipules; blade lanceolate or ovate to elliptic or oblanceolate, (25—)58—105 × (8—)15—30+ mm, dark green, long–tapered at base, serrate on margins, acute at tip, pinnately veined with midrib conspicuously raised on lower surface, short–hairy with hairs downward–arching, upper surface ± glossy.
Inflorescence cymes paired at each node subtending by leaflike bract, opposite decussate, cyme 1—5–flowered, bracteate, short–pilose and glandular–pubescent; bracts 2 subtending peduncle 2, leaflike, narrowly ovate, to 50 mm long, with basal lobes but not clasping; peduncle stemlike, internodes mostly 35—40 mm long, glandular–pubescent; bract subtending cyme leaflike, lanceolate, to 35 × 8 mm, with basal lobes; bractlet subtending pedicel acuminate–lanceolate, to 8 mm long, decreasing upward; pedicel 3—4 mm long increasing 2× in flower and fruit.
Flower bisexual, bilateral, 14—25+ mm across; calyx 2–lipped, deeply 5–lobed, 11—12 mm long, green, faintly parallel–veined, outer surface glandular short–pilose; tube < 1 mm long; lower 2 lobes triangular overlapping at base, 10—10.5 × 3.5—4.2 mm, with membranous margin to midpoint, upper 3 lobes ovate, the largest 9.5—10 × 5 mm overlapping inner 2 9 × 4 mm, cordate at base and somewhat jagged on margins; corolla 2–lipped, 5–lobed, 36—38 mm long; tube ± 3–sided, 9—9.5 × 4 mm, pinkish and white, 2 sides with 5—6 veins, at base 3 mm across, upper portion ± bell–shaped and somewhat inflated; throat funnel–shaped, ca. 12 mm long, light purple to pale purple (white) with many parallel veins, inside throat with ca. 7 deep purple honey guide lines on floor; lips with sinuses 9—10 mm deep, upper lip 2–lobed, lobes overlapping on inner margins, rounded, ca. 6 × 8—9 mm, with scattered glandular short–pilose hairs; lower lip 3–lobed; stamens 4 fertile + 1 staminode, lower stamens attached at base of corolla, upper stamens attached 9—10 mm long from base of corolla (top of corolla tube); filaments somewhat compressed side–to–side, sigmoidal, to 20 mm long, on lower side opposite purple nectar guides; anthers ± versatile, dithechal, horseshoe–shaped, ca. 3 × 2.5 mm, frosty light violet (glaucous), longitudinally dehiscent; pollen white; staminode arising from upper side of throat, straight, ca. 22 mm long, white with orangish hairs on flat upper surface except at base, upper 5 mm compressed side–to–side and purple–red; nectary disc around base of ovary, wavy with 5 cycles, 0.2 × 2 mm diameter, green to dark green; pistil 1; ovary superior, ovoid, ca. 3 × 2.2 mm, green, steeper on upper side, glabrous, 2–chambered, each chamber with many ovules attached to center; style cylindric, 22—23.5 mm long, green at base and white above; stigma terminal.
Fruit capsule, 2–valved, many–seeded, ovoid, 9.5—17 × 5.5—12 mm + beaklike tip (style) to 4 mm long and slender portion above, brown or golden brown to dark brown, often pinched below beak, hard–walled, veiny, tardily splitting from top downward.
Seed irregular polyhedral with 4—7 faces and wings or ridgelike edges, 2—3.5 × 1.1—2 mm, black, pitted (collapsed cells).
A. C. Gibson