Sonchus tenerrimus

Linnaeus

Sp. Pl. 2: 794. 1753.

Common names: Slender sow-thistle
Introduced
Treatment appears in FNA Volume 19. Treatment on page 276. Mentioned on page 274.

Annual, biennials, or perennials, 10–80 cm. Stem bases soft to hard, herbaceous, often hollow. Leaves: blades of mid cauline oblong, 3–20 × 2–6 cm, bases auriculate, auricles ovate to lanceolate or linear, ± straight, obtuse to acute, margins usually pinnately lobed, lobes ± rhombic to lanceolate (constricted at bases) or ± linear, terminals ± equaling laterals, entire or dentate. Peduncles usually setose- to stipitate-glandular, often tomentose as well, sometimes glabrous. Involucres 10–12+ mm. Phyllaries usually setose- to stipitate-glandular, sometimes tomentose as well. Corollas: ligules longer than tubes. Cypselae reddish brown, oblanceoloid, 2.5–3.5 mm, ribs 1–3 on each face, faces transversely rugulose or tuberculate across and between ribs; pappi 5–8 mm. 2n = 14.


Phenology: Flowering Mar–Jun.
Habitat: Disturbed sites, often on ballast
Elevation: 0–200 m

Distribution

V19-382-distribution-map.gif

Introduced; Calif., s Europe, w Asia, n Africa.

Discussion

Sonchus tenerrimus was known historically on ballast from Alabama, Pennsylvania (Philadelphia), New Jersey, New York, and, possibly, Quebec.

Selected References

None.

Lower Taxa

None.