Antennaria densifolia A.E. Porsild Synonyms: ellyae

Global Distribution: Rocky Mountain cordillera in , Yukon, Northwest Territories; disjunct in and Montana.32

Alaska Distribution: Intermontane Boreal.

Ecoregion Occupied: North Ogilvie Mountains.

Conservation Status: S2 G3; BLM Sensitive.

Description24, 26, 33

2 to 5 heads per cluster

Leaves covered in gray hairs on both sides

Basal 3 to 7 mm long, spatulate to cuneate

1 cm Densely tufted

Stolons 1 to 2 cm long

Illustration by Matthew L. Carlson 7

Antennaria densifolia

General: 3.5 to 16 cm tall, densely tufted with stolons 1 to 2 cm long.

Leaves: Basal leaves densely congested, 1-nerved, spatulate to cuneate, 3 to 7 mm long, 2 to 5 mm wide, gray-hairy on both sides; stem leaves linear, 2 to 13 mm long, upper ones flagged.

Flowers: Flower heads arranged in cymose clusters of 2 to 5; involucres woolly at the base, 4.5 to 7.5 mm tall on pistillate plants, 3 to 6.5 mm tall on staminate plants; involucral bracts lanceolate, brown to black near the tips, arranged in 2 or 3 series; florets 2.5 to 4.5 mm long on pistillate plants, 2 to 3.5 mm long on staminate plants.

Fruits: Achenes 0.8 to 1.5 mm long, glabrous with hairy bristles 2.5 to 3.5 mm long.

© Rob Lipkin

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Antennaria densifolia

Ecology

Elevation: Found from 600 to 1,580 m in Alaska and Yukon.

Landform: Subalpine slopes, alpine slopes, alpine ridges, rock outcrops.

Soil Type: Medium-sized talus, scree, gravel, rocky soil, mineral soil; associated with calcareous substrates.34

Moisture regime: Mesic to dry.

Slope: Moderate to steep slopes; usually 20° to 30° slope.

Aspect: Predominantly west to south to southeast; less commonly northeast or northwest.

Vegetation type: Sparsely vegetated, dwarf shrub tundra, open spruce woodlands, grasslands; usually in barren microsites.

Associated species: Arctous rubra, Cassiope tetragona, Dryas integrifolia, Festuca altaica, Pedicularis capitata, Pedicularis lanata, Picea glauca, Salix reticulata, Silene acaulis.

Longevity: Perennial, longevity unknown.

Phenology: In flower early June, probably earlier.

Population estimate: There are nine known occurrences in Alaska; populations range from few individuals to locally common.

Reproductive biology: Dioecious, the majority of populations include staminate plants and are located in previously unglaciated regions; only 3 populations that include staminate plants occur in previously glaciated regions.35

Similar Species24, 33

Antennaria densifolia can be distinguished from superficially similar Antennaria taxa by the differences in morphology and habitat shown in the table below.

Species Basal Leaves Stolons Habitat Spatulate to cuneate, 3 Antennaria Calcareous talus to 7 mm long, 2 to 5 mm 1 to 2 cm long densifolia and scree, tundra wide Narrowly spatulate to Antennaria oblanceolate, 6 to 25 Alpine and arctic 1 to 7 cm long alpina mm long, 2 to 7 mm tundra wide Narrowly spatulate to Antennaria oblanceolate, 10 to 30 0.5 to 1.0 cm Dry slopes, friesiana ssp. mm long, 2 to 4 mm long gravelly frost boils friesiana wide

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Antennaria densifolia

1 cm

ALA 129882

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