Effect: The anti-plant shell spell creates an invisible barrier which keeps out all creatures || missiles of living vegetable material.

Thus, the druid (and any creatures within the shell) is protected from attacking plants or vegetable creatures such as shambling mounds or treants.

Duration: The spell lasts for one turn per level of experience of the druid. <e>

Anti-Plant Shell: Neither the PH nor the
DMG address a particularly important
point; ie. is the spell mobile or NOT? It
would appear it is NOT, ie. the center
of the area of effect is the spot at which
the caster cast the spell, and it does NOT
move.  See comments on anti-animal shell.
(Imagine #30)