Four plants are named here, but only three of them are of one kind. Pick the odd one out: Banyan, Neem, Bamboo, Peepal.

The banyan, the neem and the peepal are trees: each stands on a solid woody trunk that thickens ring by ring as the years pass. Bamboo is a giant grass, its stem hollow and divided by joints, and it never lays down wood in that way. It passes for a tree because it grows tall and shades a courtyard as well as any, but the tie among the other three is the woody trunk.