The recent teaser details for the "Dark Knight Rises" gave me an idea of what may be happening....As you may remember the article tells that the trailer shows Bruce Wayne making his way to the "League of Shadows." Which reminded me of a very important flower that Bruce was suppose to carry with him. (Reminder: I have no idea if this has been thought of before.)
#1
First of the flower is a very imporant thing for the League of Shadows. It shows how strong a man is or how strong it can make a man. The current Ras Al Ghul newest and best apprentice is the newest person chosen to destory Gotham
City. The League has created a new weapon from the flower. Creating the vemon.
#2
Bane finds the flower on his own. He drops it on his way up the mountain and decideds to continue instead of returning for the flower. He is not aloud to join and becomes angry at the League of Shadows. Knowing of the fear attack in "Batman Begins" he sets out to destory Gotham on his own. He picks many of the flowers and take them with creating the venom on his own. Then he sets out to do what the League of Shadows could not do to prove that he is worthy.
May be Nolan gave us a hint.
Just ideas thinks for reading.