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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, biennial [perennial herb]. Stem: erect. Leaf: simple, basal and cauline, alternate, reduced upward, decurrent as spiny wings, spiny-dentate and pinnately lobed, glabrous to tomentose; basal tapered to winged petiole; cauline sessile. Inflorescence: heads discoid, 1–20 at branch tips; involucre cylindric to spheric; phyllaries graduated in several series, spine-tipped; receptacle flat, epaleate, ± white bristly. Flower: corolla white to pink or purple, tube long, slender, throat abruptly expanded, short, lobes linear; anther base short-sagittate, tip oblong; style tip cylindric above slightly swollen distal node, branches very short. Fruit: ovoid, slightly compressed, glabrous; base slightly angled; pappus of many flat, minutely barbed bristles.
± 90 species: Eurasia, eastern Africa. (Latin: ancient name for a kind of thistle) [Keil 2006 FNANM 19:91–94]

Key to Carduus

1. Phyllaries generally > 2 mm wide; heads generally solitary, conspicuously peduncled; involucre 2–7 cm diam ..... C. nutans

1' Phyllaries generally <= 2 mm wide; heads 1–several, often clustered at branch tips, short-peduncled or sessile; involucre 1–3 cm diam

2. Involucre ± spheric or hemispheric ..... C. acanthoides subsp. acanthoides

2' Involucre cylindric or narrowly ellipsoid

3. Heads generally 2–5 per cluster; phyllaries not scarious-margined, bases ± persistently loosely tomentose, tips scabrous ..... C. pycnocephalus subsp. pycnocephalus

3' Heads 5–20 per cluster; phyllaries scarious-margined, bases glabrous to sparsely tomentose, tips glabrous or barely scabrous, sometimes minutely scabrous-ciliate ..... C. tenuiflorus


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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