Bidens frondosa (Common Beggarticks) - photos and description
General: Annual plants with an upright growth habit, branching towards the top. Stems glabrous, often purplish.
Flowers: Flowers orange-yellow, lack ray florets, individual disk flowers measured at 1 mm diameter, disk flower head measured to 8 mm diameter, flower heads 12 mm long. Inner bracts lanceolate, flower heads subtended at base with 6 to 8 leafy bracts.
Leaves: Leaves opposite, pinnately divided into 3 leaflets, the terminal leaflet larger and stalked. Leaf highlighted in photograph above was 10 cm long (including petiole) and 6.5 cm wide. Terminal leaflet was 7.5 cm long and 3 cm wide. Leaves serrate, ciliate, bottom of leaves with a few hairs.
Height: Height listed in Budd's Flora to 100 cm, we measured plants to 100 cm tall.
Habitat: Wet places and along stream banks in the prairies, parklands, and boreal forest.
Abundance: Very rare, ranked as an S3 (as of 2021) by the Saskatchewan Conservation Data Centre.
Origin: Native.
Similar species: This plant is quite similar to Bidens vulgata, however the flower heads of Bidens frondosa have 6 to 8 outer involucral bracts, whereas the flower heads of Bidens vulgata have 13 to 16 outer involucral bracts. The flower heads on Bidens frondosa are smaller in diameter, usually 8 mm in diameter, while Bidens vulgata's flower heads can grow to 30 mm in diameter.
When and where photographed: Photos taken August 14th, seep on hillside, shady aspen woods, Qu'Appelle Valley, about 30 km north of our home in Regina, SK.