Giant Ragweed (Ambrosia trifida) - 2016-8-23 Russell Peterson Urban Wildlife Refuge, Wilmington, DE

-native
-aka great ragweed, Texan great ragweed, tall ragweed, blood ragweed, perennial ragweed, horseweed, buffaloweed, and kinghead
-flowers getting ready to open and release their pollen

https://florapittsburghensis.wordpress.com/2010/09/05/giant-ragweed-ambrosia-trifida/