Carduus pycnocephalus
Carduus
compact-head thistle, Italian plumeless thistle, Italian thistle
chardon, plumeless thistle
erect, simple to much branched, (spiny-winged).
basal and cauline; petiolate or sessile;
blade margins spiny dentate, often 1–2-pinnately lobed, faces glabrous or hairy, eglandular.
flat, epaleate, bearing setiform scales (“flattened bristles”).
several–many;
corollas white to pink or purple, ± bilateral, tubes long, slender, throats short, campanulate, abruptly expanded from tubes, lobes linear;
anther bases sharply short-tailed, apical appendages oblong;
style branches: fused portions with slightly, minutely puberulent, swollen basal nodes, distally papillate or glabrous, distinct portions very short.
many in 7–10+ series, linear to broadly ovate, bases appressed, margins entire, apices ascending to spreading or reflexed, acute, spine-tipped.
discoid, borne singly or 2–20 in dense clusters or corymbiform arrays. (Peduncles naked or leafy-bracteate, spiny-winged or not winged.) Involucres cylindric to spheric.
ovoid, slightly compressed, faces smooth, glabrous, attachment scars slightly lateral;
pappi persistent or falling in rings, of many minutely barbed, basally connate bristles or setiform, minutely barbed scales (“minutely flattened bristles”).
= 8, 9, 10, 11, 13.
Carduus pycnocephalus
Carduus
Subspecies 2 (1 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species ca. 90 (5 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Phyllary appendages 2–7 mm wide, usually wider than appressed bases; peduncles often elongate, distally wingless; heads often nodding, usually borne singly or in leafy corymbiform arrays; involucres 20–70 mm diam | C. nutans |
1. Phyllary appendages 0.5–1.5 mm wide, usually narrower than appressed bases; peduncles short, if present, usually winged throughout or wingless only near tip; heads erect, 1–many, often clustered at branch tips; involucres 7–30 mm diam | → 2 |
2. Involucres spheric or hemispheric | → 3 |
2. Involucres cylindric or narrowly ellipsoid | → 4 |
3. Corollas 13–20 mm; heads 18–25 mm; involucres 14–20 mm; abaxial leaf faces glabrate except for long, curled, septate hairs along veins | C. acanthoides |
3. Corollas 11–16 mm; heads 15–18 mm; involucres 12–17 mm; abaxial leaf faces sparsely to densely tomentose with fine, nonseptate hairs and often with curled, septate hairs along veins as well | C. crispus |
4. Heads 1–5 at ends of branches; phyllaries not scarious-margined, ± persistently tomentose, distally scabrous on margins and faces | C. pycnocephalus |
4. Heads 5–20 at ends of branches; phyllaries scarious-margined, glabrous or spar- ingly tomentose, distally ciliolate or glabrous | C. tenuiflorus |
- Local floras:
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
