168 NATURE STUDY AND AGRICULTURE 
common thistles because the plant is smaller, the stems thinner, 
and not often over two feet high; it has more branches, and 
each branch has several flower heads; these 
CANADA THISTLE 
thistles. 
heads are not covered with prickly spines, but 
the rest of the plant is more prickly than other 
The flowers are a paler purple and 
the leaves are darker green. This thistle, like so 
many other weeds, was introduced from Europe. 
It came by way of Canada, hence the name. 
13. Russian Thistle: Russian Cactus. — 
This is neither a thistle nor a cactus, and 
it does not look at all like 
such plants. It is much 
branched and very bushy in 
form. When young it is dark 
green, and has soft, narrow, 
needle-shaped leaves. With 
age the whole plant becomes 
more rigid and the leaves 
develop formidable, prickly 
spines. After the frost has 
killed it the wind easily breaks it 
loose from its moorings and carries 
it over the country, dropping seeds 
as it rolls along. 
14. Red Root: Rough Pigweed. 
— This is one of the plants relished 
by pigs and bearing the name pig- 
weed. It is more troublesome in 
gardens and potato grounds than in 
grain fields. It is somewhat hairy 
and rough; usually not much over 
ke 
Russian THISTLE 
