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Penstemons in Western Nebraska[1][2]
Joyce Phillips Hardy and RonaldR.WeedonChadronState College Herbarium Chadron, Nebraska69337
Hardy, Joyce P and Weedon, Ronald P. 1989. Bulletin of the American Penstemon Society48(1):2-7.Penstemons are an impressive part of Nebraska's flora, adding color and variety to the native grasslands and roadsides. Several unusual and interesting penstemons have been found during a scientific inventory of natural vegetation in the western part of the state completed in the last several years. Craig C. Freeman, in his A Biosystematic Study of the Genus Penstemon (Scrophulariaceae) in the Great Plains (1981), lists ten native penstemon species in Nebraska, of which eight occur naturally in the western one-half of the state. We discuss here the penstemon species of western Nebraska, their morphology, and their known ranges in the Great Plains. We also call attention to a recent collection of a penstemon species not included in Freeman's work for the state of Nebraska.
Penstemon albidus is a perennial plant with a branching caudex of one to five stems, ranging in height from 8-20" in our area. The leaves are relatively broad and roughly hairy. In June the funnel-shaped, weakly two-lobed flowers form a dense spike. They are white to faintly pink or violet, and are glandular-pubescent externally. Red or reddish-purple nectar guides line the internal surface of the floral throat. The staminode is moderately to slightly bearded with twisted yellow hairs. This is the most widespread of the Great Plains penstemons, ranging throughout all but the southeastern one-quarter of the region (Great Plains Flora Association, 1977). The species is common in sandy loam to sandy soils of the Great Plains (Figure 1).
Penstemon angustifolius is a common species in the Great Plains, blooming from May to June. The morphology of this species is extremely variable. The typical plants (P. a. var. angustifolius) have very narrow leaves and floral bracts, and deep blue-purple flowers with yellow-bearded staminodes and red-purple guidelines. These plants are typically northern in distribution, ranging southward from North Dakota and Montana into northern Colorado and mid-Nebraska (Figure 2). Plants of the variety caudatus are slightly taller, to 18" in height in our region, with broader stem leaves. The flower colors are more variable, from lighter blue or pink to deep blue-purple, and the bracts widen before narrowing to their pointed tips. Penstemon a. variety caudatus is more southern, ranging from Nebraska southward and westward to northern New Mexico and northwestern Arizona. Our recent collections have extended the known range of P. a. var. caudatus into the northern tier of counties in the western half of Nebraska(Figure 3). Where the range of the two varieties overlap throughout Nebraska, southern Wyoming, and northern Colorado they freely hybridize and produce offspring with varying combinations of the parental characters. Both varieties do well, and seed set appears to be very good in our area. These plants add beautiful floral color to the landscape from May through June, and the variety of leaf shape and flower color add subtle (or sometimes not-so-subtle) nuances within a large population.
Penstemon buckleyi is a stout, glaucous perennial with thick, firm leaves. One to five stems are produced from the short crown or branched caudex. Its stiff, glaucous gray stems reach nearly 20" in height. The narrow, elongated thyrse inflorescence has slender, pale pink or lavender to very pale blue trumpet flowers. Three to five flowers are produced in each cyme on either side of the flowering stalk from April to June. Up to twenty verticillasters of these cymes are produced on the stem. Prominent reddish or reddish-purple nectar guides and golden-yellow staminodes bearded to one-half their length highlight the bottom of the fully opened flower. This species is found on sandy soils from north-central and southwestern Kansas to extreme southeastern Colorado, south to central Texasand eastern New Mexico(Flora of the Great Plains, 1986). In 1987 Joyce discovered it in a remote valley in BannerCounty in the western Panhandle of Nebraska. This appears to be the first collection of the species for the state. Cattle from northern Texas had been shipped to this pasture, and they may have imported the seed into this locale (Figure 4). Determination of this specimen was provided by Craig C. Freeman from the State Biological Survey of Kansas, Lawrence, Kansas.
Penstemon cobaea is a gorgeous component of our native flora. This robust perennial produces large flowers of a white or pink to pale violet-purple color from late April through June. Magenta or violet guidelines and a golden-yellow bearded staminode highlight the large, nearly bell-shaped flower. The height of this plant is 15-20" in the northern limits of the range of the species, and up to 24" in the southern portion. The thick, lanceolate leaves are acute or rounded on the tips. The calyx is glandular and viscid. This species is normally found on calcareous, gypsiferous or sandy loams in the southwestern Great Plains. It ranges from Nebraska and southern Missouri to western Arkansas, eastern Oklahoma and eastern Texas. In the summer of 1986 we collected healthy specimens from KimballCounty in the very southwestern part of the Nebraska Panhandle. The following year Joyce collected the plant approximately 40 miles to the northeast in a roadside ditch in BannerCounty. In 1988 five colonies were seen in BannerCounty along an eight mile stretch in the roadside ditch of Highway #71. These plants were doing well on the lower slopes of the ditch incline in sandy to sandy-loam soils with calcareous rocks. These naturally-occurring colonies represent a major extension of the previously known range of the species (Figure 5).
Penstemon eriantherus ranges from western North Dakota to Montana, southward to western Nebraska and north-central Colorado. In Nebraska, this plant is most commonly seen on slopes and sides of buttes, although occasionallyit can be found in dry sandy or gravely prairie soils. The perennial plant produces one to five stems from the caudex-topped taproot. These stems range to 15" in height and are often quite hairy. Leaves are widely lanceolate, rough-hairy, and sometimes purplish on the lower surfaces. Flowers appear from May to July, and are lavender or pale pink in color. They are strongly bilabiate, viscid-pubescent externally, and have deep reddish-purple guidelines internally. The palate is densely covered with pale yellow hairs. Our recent collections extend the known range of this plant southward to Scotts Bluff, Morrill, and GardenCounties of Nebraska (Figure 6).
Penstemon glaber is an attractive plant ranging from southwestern North Dakota and north-central South Dakota west to northwestern Wyoming and southward to western Nebraska and southeastern Wyoming. The much-branched caudex yields several to many stems 20-25" in height. The dark glossy green leaves are entire-margined and thick. The trumpet-shaped flowers are deep blue or bluish-purple on the back, and light blue or white on the face, blooming from June to September. Sunshine intensity and rainfall alter the depth of the flower hue. During wet cool periods the floral color may be quite pale (Barr, 1983). The flowers are strongly bilabiate and internally lined with reddish-purple nectar guides. The staminode is glabrous or slightly bearded at the tip with pale yellow hairs. Found on sandy or gravely soils of the Great Plains, it is infrequent in native prairies, on river bluffs, loamy slopes, and on limestone crevices in full or partial sun (Figure 7).
Penstemon gracilis is found in the northern half of the Great Plains, from Nebraska northward through the Dakotas and Montana (Figure 8). This plant grows on sandy or gravely prairie soils. It is a slender perennial, up to 20" in height, with one to four stems from a slender herbaceous caudex. The stems are hairy, and commonly reddish above. Leaves are small and dark green. The bilabiate flowers appear in May to August. They are pale lavender to mauve, lighter-colored within, and lined with purple or mauve nectar guides. The staminode is bearded with stiff, golden-yellow hairs.
Penstemon grandiflorus is naturally scattered in localities from North Dakotato Nebraska, eastern Kansas and eastern Oklahoma (Figure 9). This tap-rooted, stout perennial reaches to 37" tall. The leaves are entire and firm, thick, glabrous and glaucous, and spatulate to obovate in shape. The flowers appear in April through July and are distinctly bilabiate, with their throats abruptly inflated. The large, pink to bluish-lavender or pale blue flowers are internally highlighted by magenta guidelines and golden-yellow bearded staminodes. The flowers are very attractive in these color variances, but the snow-white form with the barest touch of pink guidelines must be termed strikingly beautiful. In June of 1988, plants with these beautiful, pale flowers in a roadside ditch south of Chadron, Nebraska, were marked so we could return to gather seeds. Unfortunately, the Nebraska Department of Roads mowed off the plants and the accompanying metal-stalked flags.
Another attractive color variation is the white-flowered form of Penstemon haydenii. In 1979, Wayne and Opal Keller showed us a slide of a pure whiteflower Mrs. Keller had photographed in 1970. The pristine, snow white flower with no hint of color was breathtaking. On our extensive searches for colonies of Penstemon haydenii, we occasionally find a pure white flower. More commonly, however, the flowers are a pale, milky blue or milky lavender. James Stubbendieck of the University of Nebraska states that the white form does not set seed well, and our field work verifies this statement. The white flowers do not have the intensity of fragrance found in the colored forms. The poor seed set could therefore be a result of the lack of pollinator attraction. Dale Lindgren and Daniel Schaaf of the University of Nebraska West Central Research Center at North Platte have been attempting to breed a white-flowered form. Once they successfully produce a white-flowered plant in the horticultural setting, they may then be able to propagate it through tissue culture techniques. It is certainly deserving of the effort.
Penstemon haydenii, as an endemic to the Nebraska Sandhills, naturally grows only in the wind-eroded blowouts and their nearby slopes of sand deposition (Figure 10). The long, narrow, glaucous leaves are set low on the 10-24" stalk. Broad, spoon-shaped bracts normally subtend the very large, milky-blue to milky-lavender flowers, although we have found young flowering plants which lack the characteristic broad bracts. Flowers appear from late May through July. The fragrance is distinctive and carrying, strong yet not overpowering, "enticing to bees and pleasing to human senses" (Barr, 1983).
Where Penstemon haydenii grows in close proximity to Penstemon angustifolius a great deal of variability occurs in the latter species. Freeman (1981) postulated that Penstemon haydenii may be a derivative from a past hybridization between P. angustifolius and P. grandiflorus. These plants are pollinated by a variety of insect species, and there is thus a potential of cross-pollination.
We have been involved in the search for new colonies of Penstemon haydenii, as well as monitoring known locations for over eleven years. Claude Barr (1983) stated that "this is one of the most distinctive, intriguing, and beautiful of the penstemon species." Field work on the population dynamics and ecology has added much to our knowledge of this beautiful and rare plant It offers unique problems to the scientist, and its beauty is intriguing to the gardener. Monitoring continues for Penstemon haydenii, and we continue to search for new locations of other penstemons in our area as we carry on with field work on the native flora of western Nebraska.
ACKNOWLEDGMENTS
Funding support for this paper was provided by the Chadron State College Research Institute. We also thank Ralph Brooks of the University of Kansas Herbarium for the loan of comparative specimens of Penstemon buckleyi, and Craig C. Freeman of the State Biological Survey of Kansas for determination of our specimen of Penstemon buckleyi.
LITERATURE CITED
Barr, Claude A. 1983. Jewels of the Plains. University of Minnesota Press,
Minneapolis. Freeman, Craig C. 1981. A Biosystematic Study of the Genus Penstemon
(Scrophulariaceae) in the Great Plains. Unpublished Master's Thesis.
KansasStateUniversity, Manhattan. Great Plains Flora Association. 1977. Atlas of the Flora of the Great Plains. The
IowaStateUniversity Press, Ames. Great Plains Flora Association. 1986. Flora of the Great Plains. University Press
of Kansas, Lawrence.
Lindgren, Dale, and Daniel Schaaf. 1988. Personal communication. Stubbendieck, James. 1988. Personal communication.
Dots on the distribution maps are given in the Atlas of the Flora of the Great Plains (1977). Stars indicate collections in the Chadron State College Herbarium which were made by the authors since the publication of the Atlas of the Flora of the Great Plains.
Penstemon buckleyi
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Penstemon gracilis
[1]Authors are from: ChadronState College Herbarium Chadron, Nebraska69337
[2]Maps of the distribution of each species has been omitted from this document.