Convallaria majalis, commonly known as the Lily of the Valley, is a poisonous flowering plant found in New Mexico.
Brock Cantillo was poisoned by Walt in an unknown way with the Lily of the Valley berry. The doctors initially thought he was poisoned by ricin as Jesse Pinkman had suggested but later discovered the true toxin. The doctors and Jesse believed that Brock came across the flower growing naturally and ate some poisonous berries. ("")
- Lily of the Valley at Wikipedia