Penstemon sect. Dissecti
Monogr. Acad. Nat. Sci. Philadelphia 1: 270. 1935.
Herbs. Stems retrorsely hairy, not glaucous. Leaves cauline, basal usually withering, opposite, not leathery, glabrous or puberulent abaxially along midrib, not glaucous; cauline short-petiolate or sessile, blade ovate, margins deeply pinnatifid to nearly pinnatisect. Thyrses interrupted, cylindric, axis puberulent, cymes 2 per node; peduncles and pedicels ascending. Flowers: calyx lobes: margins entire or erose, narrowly scarious, glandular-pubescent; corolla lavender to violet, bilaterally symmetric, bilabiate, not personate, ventricose, glandular-pubescent externally, hairy internally abaxially, throat abruptly inflated, not constricted at orifice, slightly 2-ridged abaxially; stamens included or longer pair reaching orifice, filaments glabrous, pollen sacs divergent, saccate, dehiscing incompletely, distal 1/5–1/4 indehiscent, connective splitting, sides glabrous, sutures denticulate, teeth to 0.1 mm; staminode exserted, flattened distally, 0.3–0.4 mm diam., tip straight, distal 10–20% hairy, hairs to 2 mm; style sparsely glandular-pubescent proximally. Capsules sparsely glandular-pubescent distally. Seeds dark brown to black, angled, 1.5–2.4 mm.
Discussion
Species 1.
Placement of Penstemon dissectus, the lone member of sect. Dissecti, remains uncertain. It is one of two eastern North American species with saccate pollen sacs (the other being P. multiflorus) not allied with sect. Saccanthera; molecular data provide support for including it in subg. Penstemon (A. D. Wolfe et al. 2006).
Selected References
None.