Southern Nevada (Nye and Clark Counties), western Arizona, eastern California (San Bernardino County), considered to be widely disjunct from one another (Anderson 1999). The locations in southern Nevada occur in the Mojave Desert, the location in southeast California is in the Mojave Desert, and the location in Arizona occurs in the northwest in the Sonoran Desert (Etyemezian et al. 2010). In western Arizona, it is scattered from the Hualapai Mountains covering about 100 sq. miles between the yucca and Dutch Flat (MacKay 2006).
Regularity: Regularly occurring
Catalog Number: US 855518
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): M. E. Jones
Year Collected: 1905
Locality: Good Springs., Nevada, United States, North America
- Isotype: Jones, M. E. 1908. Contr. W. Bot. 12: 61.
Comments: Desert dunes (stabilized), Mohavean desert scrub (sandy). In California, Penstemon albomarginatus is found in deep, stabilized, alluvial sands that hold its long tap root in place. It is also found in wind-blown sand at the head of canyon. In Nevada, it is found at the base of hills and mountains in wind-blown areas, dunes and loose sand washes. In Arizona, it is found in sandy loam uplands and washes in alluvials plain (MacKay 2006, Scogin 1989).
Etyemezian et al. (2010) found that in the Nevada populations that the penstemon occurred in sandy places, where there was less than 20% shrub-cover, and where there was an accumulation of carbonates in the surface soil.
Life History and Behavior
Flowering occurs from March to May. A study by (MacKay 2006, Scogin 1989) noted plants were absent in ecologically similar drainages to the one that was studied, and that this species small seeds may not be dispersed long distances, or this observation could be because suitable stabilized deep sand habitat was not available. Short distance dispersal may occur via ants, rodents or water in wet years (Scogin 1989). Etyemezian et al. (2010) report a dispersal distance of 1-15 cm from the parent plant in the one location, Hidden Valley, NV where they observed dispersal.
Flowering appears to not to be dependent on the amount of rainfall, and that established plants bloom even in very dry years using water and energy stored in their long taproots (Scogin 1989). It was observed that seedlings were more numerous in areas in California that received more accumulated rainfall runoff, and it was concluded that germination and seedling survival may be rainfall dependent (Scogin 1989). Etyemezian et al. (2010) noted that 'recruitment events' were rare and episodic, and that this is similar to Mojave Desert perennial plants, and that successive wet years favor seed production, seed germination and seedling growth.
NatureServe Conservation Status
Rounded Global Status Rank: G2 - Imperiled
Reasons: Penstemon albomarginatus is known from three widely disjunct locations: the Mojave Desert of southern Nevada, the Mojave Desert of southeastern California, and the Sonoran Desert in western Arizona. Rare in California (fewer than five extant occurrences), but occassionally locally abundant elsewhere. The primary threat to this species is habitat degradation due to land-conversion.
Environmental Specificity: Very narrow. Specialist or community with key requirements scarce.
Comments: Occurs in alluvial sands, in stabilized dunes, and washes with little scrub canopy in the Mojave and Sonoran Deserts.
National NatureServe Conservation Status
Rounded National Status Rank: N2 - Imperiled
Comments: May be threatened by military activities, ORV's, dumping, mining, and activities associated with the transmission line and pipeline.
The urban growth of Clark County, Nevada, the county that contains Las Vegas, is creating demand for a new airport in the Ivanpah Valley near where Penstemon albomarginatus occurs (Etyemezian et al. 2010). As of 2013, this project appears to be on hold. With this said, this penstemon may still be threatened by development in Clark County, NV (Etyemezian et al. 2010). Further, in Clark Co., Nevada and San Bernardino Co., California the white-margined penstemon is threatened by the development of solar farms, known as the Stateline Solar Farm Project (Ironwood 2012, Basin and Range Watch 2011).
Habitat impairment is a threat in Arizona, as part of the Hualapai Mountains Land Exchange, as the land exchange converted the western edge of the penstemon's habitat in Dutch Flat to private land. With this said, though, much of the private land in Dutch Flat will stay in its natural condition (Anderson 1999).
Penstemon albomarginatus is an uncommon species of penstemon known by the common name white-margined beardtongue. It is native to the deserts of southern Nevada and western Arizona, as well as in two desert washes in the Mojave Desert in California. It is a perennial herb with several erect stems emerging from a taproot in the sand, their base buried beneath the surface. The stem branches are hairless and somewhat waxy in texture, reaching up to about 35 centimeters tall. The oppositely arranged leaves are oblong or widely lance-shaped, pale green edged in white, and up to 5 centimeters long. The inflorescence produces several purplish-pink tubular flowers between 1 and 2 centimeters long surrounded at the bases by toothed, white-edged sepals. The flower has some hairs in the mouth, but the staminode is hairless. The flowers are pollinated by vespid wasps and probably other insects, such as carabid beetles.
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