Revision of Penstemon Section Habroanthus (Scrophulariaceae). III: Series Virgati

Abstract

Series Virgati consists of six geographically replacing species centered in the southern Rocky Mountains. Descriptions, specimen-citations, maps and a key may be used to distinguish the species. Of the six species, only Penstemon virgatus is highly variable, it consisting of four well-marked subspecies which are distinguishable by use of a key, maps, specimen-citations and descriptions. Penstemon putus is reduced to a subspecies of P. virgatus, while P. virgatus ssp. arizonicus is elevated to specific rank under the new name P. deaveri, being named for Chester Deaver of Flagstaff, Arizona. Penstemon virgatus ssp. pseudoputus is described as new, being named for its similarity to ssp. putus. KEY TO SPECIES WITHIN SERIES VIRGATI A. Leaves thick and glaucous; inflorescence much branched; staminode bearded with light-colored hairs (not dark yellow or golden); corolla and calyx not glandular, the corolla 24-29 mm long; endemic to the Mogollon Rim of central Arizona -.........-.. 12. P. nudifiorus AA. Leaves not thick and glaucous; inflorescence little branched; staminode glabrous or bearded with dark yellow or golden hairs (not lightcolored). B. Calyx and corolla glandular, the corolla 14-17 mm long; plants 0.5-2.0 dm tall; leaves linear or spatulate, 1.5-5.0 mm wide; endemic to the Aquarius Plateau, Garfield County, Utah .-..... -1.... 11. P. parvus BB. Calyx and corolla not glandular. C. Staminode bearded. D. Staminode bearded for 2/3 of its length with golden hairs; anther sacs occasionally with 1 or 2 hairs at the summit; plants 1-2.5 dm tall; corolla 14-25 nmrn long; endemic to high peaks of Colorado 10. P. hallii DD. Staminode bearded only at the tip with a tuft of yellow hairs; anther sacs strictly glabrous; corollas 16-25 mm long; plants 2-6 dm tall; endemic to the White Mountains of Arizona and adjacent New Mexico . 9. P. deaveri CC. Staminode glabrous. E. Corollas 26-34 mm long, the throat very wide, the lower lip densely white-bearded; stem and leaves glabrous; sepals 4-8 mm long; endemic to the White Mountains of southern New Mexico (not the same White Mts. as in DD, above) .. -... 8. P. neomexicanus EE. Corollas 17-28 mm long, the throat only moderately wide, the lower lip only moderately white-bearded (glabrous in ssp. pseudo putus); stem and leaves pubescent (glabrous in ssp. asa-grayii and ssp. putus); sepals 2-4 mm long (4-6 mm long in ssp. asa-grayii) 7. P. virgatus 7. Penstemon virgatus A. Gray (Figs. 1, 2). Slender to stout, pubescent or glabrous perennials (biennials?) from a suffrutescent or apparently herbaceous caudex; stems 2-9 dm