E-Flora BC: Electronic Atlas of the Flora of British Columbia

Penstemon davidsonii Greene
Davidson's penstemon
Plantaginaceae (Mare's-tail family)
(Previously in Scrophulariaceae)

Introduction to Vascular Plants

© Virginia Skilton  Email the photographer   (Photo ID #34030)

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Distribution of Penstemon davidsonii
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Species Information

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General:
Low-shrubby perennial herb, woody at the base, with or without a taproot; stems much-branched, creeping, forming dense mats; flowering shoots 5-10 cm tall, minutely hairy.
Leaves:
Opposite, evergreen, smooth but sometimes glandular-spotted, primary leaves short-stalked, thick and firm, the blades elliptic to circular, entire or minutely saw-toothed, 0.5-2 cm long, usually blunt-tipped; leaves of the flowering shoots few, unstalked, small, often bract-like, less than 1 cm long.
Flowers:
Inflorescence a compact, few-flowered, terminal raceme, the bracts and stalks somewhat glandular-hairy; corollas purple to blue-lavender, tubular, 2-3.5 cm long, distinctly 2-lipped, smooth on the outside, hairy within on the lower lip near its base and on a pair of hairy ridges; calyces 7-10 mm long, smooth to thinly glandular-hairy, 5-lobed, the lobes lanceolate to narrowly egg-shaped; fertile stamens 4, the anthers densely white-woolly; sterile stamen half as long as the fertile stamens, long yellow-bearded toward the tip.
Fruits:
Capsules, 8-11 mm long; seeds numerous, angled, narrowly winged, about 1.5 mm long.
Notes:
Two sympatric, poorly defined (at least in BC) varieties occur in BC:

1. Leaves entire, tending to be broadest above the middle; infrequent................. var. davidsonii

1. Leaves minutely saw-toothed, tending to be broadest near or below the middle; the common variety.................. var. menziesii (Keck) Cronq.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry rock outcrops, slabs, ledges and talus slopes in the montane to alpine zones; frequent in BC in and west of the Coast-Cascade Mountains to 55degreeN, rare on the Queen Charlotte Islands; S to CA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Penstemon davidsonii

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class

Minimum

Average

Maximum

Elevation (metres) 25 1715 2410
Slope Gradient (%) 0 42 119
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
37 180 355
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 1 8
Modal Nutrient Regime
Class
B
Number of field plots
 species was recorded in:
82
Modal BEC Zone Class
ESSF
All BEC Zones (# of stations/zone) species was recorded in: AT(8), CMA(14), CWH(5), ESSF(33), ICH(1), IDF(1), MH(11), MS(8)

Climate

The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is alpine tundra & boreal.

Taxonomic and Nomenclatural Links

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General References