This spell causes nearby thorny plants to launch a burst of 1d6 thorns plus 1 thorn per caster level. Each of these thorns causes 1 point of damage. For every three caster levels, one additional creature can be affected by the spell.
Thus, a 6th-level druid can affect three orcs in a 20-foot radius, each suffering 1d6+6 points of damage. Victims who make a successful saving throw vs. spell suffer only half damage.
This spell is useless against targets wearing armor heavier than chainmail or who have a natural AC of 4 or better. Also, the spell fails if cast in an area devoid of plant life.
The verbal component is a low, shuffling sound, followed by a closing and opening of the caster's hand.