Bull Thistle (Cirsium lanceolatum) is the thistle 
that we most often see in fields and pastures. It is one 
of the largest of the genus, its heads often measuring 
three inches across. The stem is stout and simple, and 
grows from 1 to 3 feet high; it is hairy and angular in 
section and grows from a biennial rootstalk. 
The flower heads are very large, two to three and 
one-half inches across and usually solitary, although 
frequently two heads grow on the same stalk. The 
leaves are lance-shaped, green, clasping, rather hairy, 
pinnatifid and armed with short, stout priekles. Just 
below the flowers are several small bract-like leaves, 
also armed with sharp prickles. All this armor tends 
to discourage pilfering insects from crawling up the 
stem; should they persist and reach the large involucre, 
which is also armed, they will find that, in addition, it 
is slightly sticky, and presents an impenetrable barrier 
to their upward progress. This species is common from 
Me. to Del. and Pa. It blooms from July until Sept. 
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