Warning: This is 3.0 Edition material. It is possible that there is more recent 3.5 Edition version.
Inaccurate?

Darkseed

(Masters of the Wild: A Guidebook to Barbarians, Druids, and Rangers)

Transmutation
Level: Druid 0,
Components: V, DF,
Casting Time: 1 action
Range: Close (25 ft.+ 5 ft./2 levels)
Target: One normal plant or plant creature
Duration: 1 day
Saving Throw: Reflex negates
Spell Resistance: Yes

If the target fails its Reflex save, it takes 1 point of damage when the spell is cast and another every hour while it is in effect.
Hardness is ignored for damage from darkseed.
It would take weeks to kill a large tree with successive applications of this spell, but a small plant would die in a matter of hours.
Darkseed does not affect plant creatures with Wisdom and Charisma scores.

Comments on this single page only