Flora of the Hawaiian Islands
Dicotyledon Literature for Cirsium vulgare
Wagner et al., 1990, 1999.
   Asteraceae -- The Sunflower Family Bibliography
      Cirsium vulgare

Common name(s): thistle, bull thistle, pua kala
General Information
DistributionNative to Eurasia.In the Hawaiian Islands, naturalized on Ni`ihau, Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Kaho`olawe, Hawai`i.

Biennial herbs 5-15 dm tall; stems conspicuously spiny-winged from the decurrent leaf bases, spreading hirsute to arachnoid pubescent.
Leaves oblanceolate to elliptic, 10-20(-40) cm long, 3-8 cm wide, upper surface with pungent bristles, lower surface arachnoid pubescent to hirsute, coarsely toothed to irregularly pinnatifid, the larger lobes toothed or lobed, base decurrent for the whole internode or the upper ones less so.
Heads several; involucre 2.5-4 cm high, 2-4 cm in diameter, sparsely arachnoid pubescent to woolly, the bracts spine-tipped, the spines 2-3.5 mm long; corollas purple, 26-36 mm long.
Achenes 3-5 mm long.
2n = 56-60, 68, 102