ANNUAL SOWTHISTLE, Sonchus
oleraceus L. 1, top of plant in bloom; 2, seed. Annual,
reproducing by seed. Stem smooth, erect, 1 to 6 feet (0.3 to 1.8
m) tall, with a milky juice. Leaves at base of stem more or less
petioled; upper leaves clasping the stem with pointed projections; deeply
cut, usually with a large end segment, margins with soft prickles. Flower
heads about 3/4 inch (1.9 cm) across, of light yellow ray flowers;
borne on numerous branches at top of plant. Found in gardens, pastures,
wasteland, and roadsides.
SPINY SOWTHISTLE, Sonchus asper (L.)
Hill. Similar to the above. Annual. Leaves nearly entire,
prickly-edged, stem leaves clasping the stem with large, rounded, earlike
lobes.