Symphyotrichum lanceolatum (Willow Aster) - photos and description





Stems hairy in lines.

Stems hairy in lines.

Leaves usually entire

Leaves sometimes have small teeth

General: Erect plants with branching growth habit, plants are rhizomatous. Stems hairy in lines.

Flowers: Flower heads numerous in leafy panicles, white in colour (field guides also list flower heads as pink to bluish-purple). I measured flower heads at 2 cm diameter.

Leaves: Leaves alternate, stalkless, linear to narrowly lanceolate, usually entire but sometimes toothed. We measured a leaf at 11 cm long and 1 cm wide.

Height: Height listed in Flora of Alberta to 120 cm. Plant in above photo was 135 cm tall.

Habitat: Stream banks, ditches, marshes, and moist spots.

Abundance: Common.

Origin: Native.

Synonym: This plant is listed in some of the field guides we use as Aster hesperius.

Similar species: This plant is similar to Symphyotrichum boreale. To identify Symphyotrichum boreale:
    - leaves uniform < 5 mm wide
    - inflorescence few headed, generally < 10 flower heads, inflorescence flat-topped
    - plants are few-branched.

To identify Symphyotrichum lanceolatum:
    - leaves > 5 mm in width
    - inflorescence many-headed, flower heads generally > 10 present
    - branching growth habit.

When and where photographed: Took the above photos August 20th, moist ditch, Duck Mountain Provincial Park, about 300 km northeast of our home in Regina, SK.