Symphyotrichum pygmaeum Asteraceae (Lindl.) Brouillet & Selliah Synonyms: Aster pygmaeus, Aster sibiricus ssp. pygmaeus, Eurybia pygmaea
Global Distribution: Arctic North America from northeastern Alaska to Nunavut.
Alaska Region: Arctic Tundra.
Ecoregions Occupied: Beaufort Coastal Plain.
Conservation Status: S2 G2G4; BLM Sensitive.
Description191
Involucres 9 to 12.5 mm Ray florets purple, long, sparsely covered with disc florets yellow 2 cm glandular hairs
Upper stems and peduncles densely covered with soft, woolly hairs
Upper stem leaves 13 to 19 mm long, 2 to 4.5 Stems 1.5 to 15 cm mm wide long, decumbent to ascending Lower stem leaves 3 to 5 cm long, 3 to 10 mm wide Illustration by Matthew L. Carlson
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Symphyotrichum pygmaeum
General: Perennial herb from branched caudex and long rhizomes; stems 1 to 10, decumbent to ascending, 1.5 to 15 cm long, purple, sparsely or densely covered with soft, woolly hairs in the upper half.
Leaves: Basal leaves spatulate, 5 to 19 mm long, 2 to 4 mm wide, entire, glabrous or sparsely covered with soft hairs in the lower half, petiolate, often withered by time of flowering; lower stem leaves sessile, sometimes clasping, lanceolate to oblong, 3 to 5 cm long, 3 to 10 mm wide; upper stem leaves sessile, sometimes clasping, lanceolate to oblong, 13 to 19 mm long, 2 to 4.5 mm wide, sparsely covered with soft, woolly hairs.
Flowers: Flower heads solitary at the ends of stems; peduncles densely covered with soft, woolly hairs; involucres 9 to 12.5 mm long with bracts in 3 to 4 rows; involucral bracts green to purple, linear to oblong, covered with soft, woolly hairs and glandular hairs; ray florets purple, 12 to 18 mm long, 2 to 3.2 mm wide; disc florets yellow.
Fruits: Achenes covered with bristles; pappi white to yellow, 5 to 7.2 mm long.
© Forrest Baldwin 2009
Ecology
Elevation: Known from near sea level to 40 m in Alaska; known from up to 220 m in arctic Canada.
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Symphyotrichum pygmaeum
Landform: River terraces, river banks, dunes, pingos; often associated with areas that are regularly disturbed by natural processes.
Soil Type: Sand, silt.
Moisture regime: Moist to dry.
Slope: Flat to moderately sloped.
Aspect: No particular aspect.
Vegetation type: Sparsely vegetated, open Dryas tundra.
Associated species: Arctagrostis latifolia, Armeria scabra, Artemisia borealis, Artemisia comata, Artemisia glomerata, Artemisia tilesii, Bistorta vivipara, Castilleja elegans, Hulteniella integrifolia, Dupontia fisheri, Juncus castaneus, Minuartia rossii, Salix arctica, Salix ovalifolia, Trisetum spicatum, Wilhelmsia physodes.
Longevity: Perennial, longevity unknown.
Phenology: Flowering July through mid-August; fruiting early August through September.
Population estimate: There are nine known occurrences in Alaska; one occurrence is locally uncommon.
Herbivory: Seeds likely consumed by insect larvae.
Similar Species191, 192
Symphyotrichum pygmaeum has in the past been included as a race of Eurybia sibirica. It is easily confused with both Eurybia sibirica and Symphyotrichum yukonense. These species can be distinguished by the morphological features described in the table below.
Species Stems Stem leaves Involucres 1.5 to 15 cm long, Lower leaves 3 to 10 9 to 12.5 mm long, decumbent to Symphyotrichum mm wide, upper sparsely covered ascending, pygmaeum leaves 2 to 4 mm with glandular lacking glandular wide hairs hairs 5 to 30 cm long, Lower leaves 1 to 4 7 to 10 mm long, Symphyotrichum erect, covered mm wide, upper densely covered yukonense with glandular leaves 1 to 2.5 mm with glandular hairs wide hairs 5 to 60 cm long, Lower leaves 3 to 35 6 to 9 mm long, decumbent to mm wide, upper Eurybia sibirica glandular hairs erect, lacking leaves 1 to 12 mm absent glandular hairs wide
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Symphyotrichum pygmaeum
2 cm
ALA 22181
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