This has still been niggling away in the back of my mind, and from its dimmest depths I've dragged up an allusion lost since my childhood. The upas tree poisons the land around, and with a side-swipe from Lear Araucaria refers to serpent's tooth. Now in classical mythology the dragon-serpent's teeth were sown and gave rise to warriors. The teeth themselves were described as poisoning the land, and the phrase "to sow dragon's teeth" has come to mean to do something that causes dispute and thus poison. I'd like to think this reference is waht Araucaria meant, such that I can maintain my healthy respect for his clueing!