Penstemon sect. Chamaeleon

Herbs. Stems retrorsely hairy or puberulent, sometimes glandular-pubescent distally or glabrescent, not glaucous. Leaves basal and cauline, basal usually absent at anthesis, opposite, leathery or not, glabrous, puberulent, or retrorsely hairy, not glaucous; basal and proximal cauline petiolate, sometimes short-petiolate or sessile (P. dasyphyllus); cauline sessile, sometimes short-petiolate (P. lanceolatus), blade lanceolate or linear, margins entire. Thyrses interrupted, ± secund to cylindric, axis glandular-pubescent or glabrous, cymes 1 or 2 per node; peduncles and pedicels ascending to erect. Flowers: calyx lobes: margins entire or erose (P. stenophyllus), herbaceous or narrowly scarious, sometimes broadly scarious (P. stenophyllus), glandular-pubescent or glabrous; corolla lavender to blue, violet, purple, red, or scarlet, bilaterally symmetric, bilabiate, not personate, ventricose or tubular-funnelform, glandular-pubescent externally, glabrous or glandular-pubescent internally abaxially, throat abruptly or gradually inflated, not constricted at orifice, rounded to 2-ridged abaxially; stamens included to exserted, filaments glabrous, pollen sacs parallel to divergent, navicular to slightly saccate, dehiscing completely or incompletely, distal 1/5 or less sometimes indehiscent, connective splitting, sides glabrous, sutures denticulate, teeth to 0.2–0.3 mm; staminode included or exserted, flattened distally, 0.3–2.6 mm diam., tip recurved, glabrous; style glabrous. Capsules glabrous. Seeds brown to dark brown, angled, 1.9–3.2 mm.

Distribution

sw United States, Mexico.

Discussion

Species 4 (3 in the flora).

Crosswhite circumscribed sect. Chamaeleon to include a group of southern species distinguished by incompletely dehiscent pollen sacs with prominently denticulate sutures. Penstemon punctatus Brandegee, a species not treated by Crosswhite, might belong here; the only specimens of that species seen were from Coahuila, Mexico.

Selected References

Crosswhite, F. S. 1966. Revision of Penstemon section Chamaeleon (Scrophulariaceae). Sida 2: 339–346.

Lower Taxa

Penstemon dasyphyllus, Penstemon lanceolatus, Penstemon stenophyllus

Key

1	Corollas scarlet to red, tubular-funnelform, glandular-pubescent internally abaxially.	Penstemon lanceolatus
1	Corollas violet to blue, lavender, or purple, ventricose, glabrous internally.	> 2
2	Thyrse axes glandular-pubescent.	Penstemon dasyphyllus
2	Thyrse axes glabrous.	Penstemon stenophyllus