Montana Field Guide

Annual. Stems erect, 30–100 cm. Herbage glabrous to sparsely puberulent. Leaves distinctly petiolate; blades divided into 3 or 5 lanceolate, serrate leaflets, 1–8 cm long. Inflorescence: heads usually few; peduncles 2–12 cm long. Involucre: outer phyllaries 10–16, oblanceolate, 8–30 mm long, ciliate, sometimes serrulate; inner phyllaries ovate, 6–8 mm long. Rays absent or 3 to 5 reduced. Disk corollas 2–3 mm long. Pappus 2, awns 2–4 mm long. Achenes flattened, 5–12 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

In Montana Bidens species have opposite leaves, involucral bracts of 2 types, awned seeds that catch your clothing, and grow in wetland habitats. Several species lack ray florets.

Tall Bur-marigold - Bidens vulgata
*Life Span: Annual.
*Leaves: Pinnately divided and with a distinct petiole.
*Flower Heads: Composed only of disc florets; ray florets absent. Outer phyllaries are 10-16 mm long.
*Pappus: With 2 awns.
*Habitat: Wet or moist places that may become temporarily inundated.

Devil's Beggarticks - Bidens frondosa
*Life Span: Annual.
*Leaves: Pinnately divided and with a distinct petiole.
*Flower Heads: Composed of disc florets; ray florets absent or inconspicuous. Outer phyllaries are 5-8 mm long.
*Pappus: With 2 awns.
*Habitat: Wet or moist places that may become temporarily inundated.

Nodding Beggarticks - Bidens cernua
*Life Span: Annual.
*Leaves: Simple or shallowly lobed and toothed. Petioles are short and distinct or sessile and winged.
*Flower Heads: Composed only of disc and ray florets.
*Pappus: Usually with 4 awns.
*Habitat: Wet or moist places that may become temporarily inundated.

Three-lobe Beggarticks - Bidens comosa
*Life Span: Annual.
*Leaves: Simple or shallowly lobed and toothed. Petioles are short and distinct or sessile and winged.
*Flower Heads: Composed only of disc florets though sometimes with inconspicuous ray florets.
*Pappus: Usually with 3 awns.
*Habitat: Wet or moist places that may become temporarily inundated.

Beck Water-marigold - Bidens beckii, SOC
*Life Span: Perennial
*Leaves: Of two types. Submerged leaves are dissected into thread-like segments. Emergent leaves are simple and toothed.
*Flower Heads: Composed only disc and ray florets.
*Pappus: Of 2-6 awns.
*Habitat: Aquatic.

Banks of ponds, marshes, slow streams; plains (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus griseocollis and Bombus impatiens (Plath 1934, Colla and Dumesh 2010).