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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.


Annual, perennial herb [shrub]. Stem: prostrate to erect. Leaf: simple or pinnate, generally opposite, sessile or petioled. Inflorescence: heads radiate or discoid, occasionally disciform, generally few in California; involucre cylindric to bell-shaped; phyllaries in 2 dissimilar series, outer generally ± leaf-like in texture, inner thinner, with transparent or scarious margins; receptacle paleate; paleae narrow, flat. Ray flower: 0 or few; ray yellow or white. Disk flower: generally many; corolla yellow, radial (or outermost white, bilateral). Fruit: narrowly club-shaped, thick or compressed front-to-back; pappus 0 or awns 1–several, generally barbed.
± 230 species: worldwide. (Latin: 2 teeth) [Strother & Weedon 2006 FNANM 21:205–218]

Key to Bidens

1. Leaf simple

2. Leaf petioled ..... B. tripartita

2' Leaf sessile

3. Fruit with ± thickened margin, prominently ribbed; palea tips yellow; ray 0 or < 15 mm ..... B. cernua

3' Fruit without thick margin or prominent ribs; palea tips ± red; ray 15–30 mm ..... B. laevis

1' Leaf pinnate

4. Fruit narrowly cylindric or slightly compressed, 4-angled ..... B. pilosa

4' Fruit wedge-shaped, flat

5. Outer phyllaries 5–8; inner phyllaries = disk ..... B. frondosa

5' Outer phyllaries 10–16; inner phyllaries < disk ..... B. vulgata


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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