Erysimum angustatum Rydb. Brassicaceae Synonyms: Erysimum asperum var. angustatum Notes: Al-Shehbaz (2010) included this taxon within Erysimum capitatum var. purshii.108
Global Distribution: Endemic to Alaska and Yukon.
Alaska Distribution: Intermontane Boreal.
Ecoregions Occupied: Yukon-Old Crow Basin, North Ogilvie Mountains.
Conservation Status: S2 G5T2; BLM Sensitive.
Description24, 25
Petals bright yellow, 12 to 20 mm long, more than 5 mm wide
Siliques 2 to 9 cm long, linear, curved with styles 3 to 4 mm long
Basal leaves linear to linear- lanceolate, 3 to 12 cm long, narrow, entire
2 cm
Entire plant pubescent with white, T-shaped hairs Caudex covered with persistent leaf bases
Illustration by Matthew L. Carlson 143
Erysimum angustatum
General: Perennial herb with many-headed caudex covered with persistent leaf bases that form a triangular pattern; long, thick root; stems several, 10 to 45 cm long; entire plant pubescent with white, T-shaped hairs.
Leaves: Basal leaves 3 to 12 cm long, linear to linear-lanceolate, narrow, entire (plants at Eagle Bluff with coarsely toothed basal leaves up to 10 mm wide were previously included within Erysimum angustatum but are apparently distinct and may belong within Erysimum asperum109); stem leaves reduced upwards.
Flowers: Flowers arranged in compact racemes, elongating in fruit; pedicels spreading to ascending; sepals oblong, half the length of petals; petals oblong-obovate, bright yellow, 12 to 20 mm long, more than 5 mm wide.
Fruits: Siliques 2 to 9 cm long, spreading to erect, linear, curved; styles 3 to 4 mm long.
© Bruce Bennett 2011
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Erysimum angustatum
Ecology
Elevation: Known from 180 to 1,100 m in Alaska; up to 1,530 m in Yukon.
Landform: River bluffs, rock outcrops, mountain slopes, cliffs.
Soil Type: Rock, scree; associated variously with calcareous, acidic, volcanic, and shale substrates.
Moisture regime: Dry, well-drained.
Slope: Usually associated with steep slopes at least up to 40°.
Aspect: Predominantly southwest to south to southeast; rarely other aspects including east and northeast.
Vegetation type: Sparsely vegetated, open graminoid steppe, open sites in aspen or birch forest; usually occurs on sites with less than 40% total vegetative cover.110
Associated species: Artemisia frigida, Bupleurum triradiatum, Calamagrostis purpurascens, Campanula aurita, Cryptantha shackletteana, Eriogonum flavum var. aquilinum.
Longevity: Perennial, short-lived.110
Phenology: Flowering late May, probably sooner, to late July; fruiting mid-June to August.
Population estimate: There are 19 known occurrences in Alaska; population sizes range from scattered individuals to several thousand individuals.111
Herbivory: Leaves on some specimens have small holes, indicating possible herbivory by insects.
Similar Species24, 25, 108
Plants similar to Erysimum angustatum but with coarsely-toothed, broad leaves occur at Eagle Bluff and are apparently distinct. Additional study is necessary, but the broad-leaved plants may belong within Erysimum asperum.109
In the past, Erysimum angustatum has been treated as a variety of Erysimum asperum because of the coarsely-toothed, broad-leaved material found at Eagle Bluff. Al-Shehbaz (2010) listed Erysimum angustatum in synonymy with Erysimum capitatum var. purshii, known from the western United States.108 However, the narrow-leaved plants are uniform across their range and are maintained here as a distinct Alaska-Yukon endemic at the species level. The name should not be confused with Erysimum capitatum var. angustatum, a highly localized endemic of California.108
Erysimum angustatum can be distinguished from other yellow-flowered Erysimum species that grow on barren, steppe, or open-wooded slopes and rock outcrops in Interior Alaska by the morphological features described in the table below.
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Erysimum angustatum
Species Leaf Hairs Petals Siliques 12 to 20 mm 3 to 8 cm long; Erysimum angustatum T-shaped long; more than 5 styles 3 to 4 mm mm wide long 10 to 15 mm 2.5 to 5.8 cm long; T-shaped or 3- Erysimum coarctatum long; 2.5 to 4 styles 0.5 to 1.5 mm rayed hairs mm wide long 3 to 7 cm long; Erysimum T-shaped or 3- 6 to 9 mm long; styles 0.7 to 3 mm inconspicuum rayed hairs 1 to 2 mm wide long 3 to 5.5 mm 1.2 to 2.7 cm long; Erysimum Predominantly 3- long; 1.5 to 2 styles 0.5 to 1.5 mm cheiranthoides or 4-rayed hairs mm wide long
Material from Eagle Bluff with broad, coarsely- toothed leaves is apparently distinct from typical Erysimum angustatum and may prove to belong within Erysimum asperum; however, further investigation is needed109
2 cm
Typical Erysimum angustatum with narrow, untoothed leaves
ALA 81244
ALA 81453
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