Great Ragweed

Great Ragweed

Ambrosia trifida

Great Ragweed is a huge impressive plant.  I've seen some that must have been 3 meters tall!  When walking through a patch of these, it seems like you're in a jungle.

When first encountered, it's hard to figure out how this plant is related to Annual Ragweed.  The leaves are different.  The size is different.  It tends to grow in large groups.  Upon examination of the flowers though, it's hard to tell the difference.  They both have the same sort of flowers.  To taxonomists, the reproductive parts are more important than the rest.  I suppose that's true for everybody. :-)

This plant looks very little like Annual Ragweed, until you look at the flowers which are quite similar.

The tri-lobed leaves of Great Ragweed are quite distinctive