Ruminate on a German flower (7)
I believe the answer is:
mullein
'flower' is the definition.
The definition and answer can be both plants as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'ruminate on a german' is the wordplay.
'ruminate' becomes 'mull' (synonyms).
'on' is a charade indicator (letters next to each other).
'a german' becomes 'ein' ('a' in German).
'mull'+'ein'='MULLEIN'
Can you help me to learn more?
(Other definitions for mullein that I've seen before include "Plant with woolly leaves" , "Plant with spikes of yellow flowers" , "Yellow-flowered plant popularly known as Aaron's rod" .)