Poisonous Clover Flower. Sweet clover contains coumarin which is non-toxic. For example ingesting even a small part of some flowers can cause symptoms whereas for others youd need to ingest a large amount to see.
All parts of the plant have toxic potential although the possibility of serious effects is usually limited to ingestions of large quantities. Sweet clover and white sweet clover Melilotus officinalis and M. Farmers who feed their cows rotten hay have this trouble frequently.
A similar clover whether in the form of hay or grass is poisonous to horses.
If ingested immediately call the Poison Control Center -- 800 222-1222 -- or your doctor. Cyanogenesis is a process that creates trace amounts of cyanide in a select few plants and fruits. To search for photos of these plants check the UC Berkeley CalPhotos. They are non-problematic if consumed fresh.