bio.wikisort.org - Plant

Bidens amplissima, also known as the Vancouver Island beggarticks,[2] is a species of flowering plant in the Asteraceae family. The geographic distribution of B. amplissima is restricted mainly to Vancouver Island on the Pacific Coast of Canada, the mainland of British Columbia, and the nearby US State of Washington.[3] There are some reports of the plant also being found in Manitoba and Nebraska, but these are almost certainly introductions.[4][5][6][7]

Bidens amplissima
Bidens amplissima
Conservation status
Special Concern (COSEWIC)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Bidens
Species:	B. amplissima
Binomial name
Bidens amplissima Greene
Synonyms[1]
Bidens cernua var. elata Torr. & A.Gray Bidens elata (Torr. & A.Gray) Sherff

Bidens amplissima is an annual growing up to 120 cm (4 feet) tall. It produces numerous yellow flower heads containing both disc florets and ray florets.[8]

Distribution

The geographic distribution of B. amplissima is restricted mainly to Vancouver Island on the Pacific Coast of Canada, the mainland of British Columbia, and the nearby US State of Washington.[3] There are some reports of the plant also being found in Manitoba and Nebraska, but these are almost certainly introductions.[4][5][6][7]

Habitat

Bidens amplissima occurs in moist or wet ditches, streambanks and pond edges.[9]

Morphology

Bidens amplissima is an annual growing up to 120 cm (4 feet) tall. It produces numerous yellow flower heads containing both disc florets and ray florets.[8]

Stem leaves are opposite, unstalked, and the lower and middle leaves are often deeply three-lobed. However, leaves are also often simple and not lobed. The leaf margin is coarsely toothed or incised, glabrous, and roughly 8–20 cm long.

Flower heads have ray and disk flowers and occur in a terminal cluster at the top of the plant. Involucral bracts are in two rows, the outer ones about 8–10, leafy, fringed with small hairs, linear-lanceolate with entire margins, up to 7.5 cm long, the inner ones narrowly egg-shaped, 8–12 mm long. Ray flowers are 8–11, yellow, 3.5–8 mm long, while disk flowers are yellow.

Fruits are achenes which are wedge-shaped with flat or concave summits. Achenes are 5–7 mm long, with retrorsely-barbed awns which are 2–4 mm long.[9]

Other species

Bidens amplissima is often confused with two closely related species, B. cernua and B. tripartita. B. amplissima can be distinguished from B. cernua, which has cartilaginous and concave achene summits, globular flower heads, and more numerous petals than B. amplissima. B. amplissima can also be separated from B. tripartita, which can be very similar in appearance, however B. tripartita lacks the ray petals.[9]

References

External links

• South Coast Conservation Program, Vancouver Island Beggarticks, Bidens amplissima

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