Legends tell of the mysterious Swamp Children - quiet spritely beings who help lost souls but none of these beliefs survive actually encountering one.
The Swamp Children are small, emaciated humanoids with exaggerated potbellies and long, wolflike muzzles. Their skin is covered in a foul, yellowish mucous which protects them against the cold as well as the vermin of the swamp. No insect will willingly come close to a Swamp Child - those that do get stuck in the viscous coating and subsequently eaten. They are well adapted to their swamp home, being fully amphibious and able to hold their breath for many minutes. They are small - generally less then 3' tall and about 40 lbs weight, but they are extremely strong. The Swamp Children normally feed on the natural flora and fauna of their swamp home, but they will gleefully feast on anything that they can overpower, and are not above cannibalism.
When hunting, groups of the Children will lurk under the surface in ambush while others will either lead or drive victims into the ambush point. Grappling and dog-piling their foes, they will attempt to force them under the fetid waters of the swamp to drown.
The Children are capable of speech and have their own langauge. Since they have no interest in other beings except as food, they do not learn other languages.
There are legends of spellcasting Swamp Children, and these are true - there are shamans within their ranks that worship demonic powers. Go to Comment
Okay, I'll address your points and add a correction.
This plant is intended as a deadly magical defence - the main sub that uses it is still under work, but it is supposed to be deadly and difficult to circumvent.
Magical winds, very fine dust masks, poison immunities, etc, are valid defences. Heavy rainfall would mitigate the deadliness as well.
Also, I was deliberately vague on how much pollen would actually cause death so it is easy to allow for lesser effects.
As to effects of Cardiac arrest, it would be equal to a non-magical death spell :)
However, I did make a mistake on this sub, so some magical alteration of the standard Digitalis is needed:
From Textbook of Materia Medica, 5th edition, 1932, page 259
Since Digitalis is slowly absorbed, and excreted still more slowly, it does not cause acute poisonous symptoms.
To achieve the desired level of lethality in line with my intent on this submission, one should instead substitute Cyanide, a much more acutely deadly toxin and one which does occur in many plants. Though I took the easy way out, and just made the toxin a variant of Digitalis. Go to Comment
A magical plant (Fungi!!!) that powerful has to have an interesting origin! Perhaps a murder victim spoke some appropriate curse on their killer as they died, and the fungus which sprung forth betrayed the murderer to his own death? Maybe? :) Go to Comment
There is a small and strange nature-worship cult that has dedicated itself to freeing vegetables. They appear usually in working pairs or trios, arriving to villages and towns separately and wearing the local garb. For some reason, they have taken to disguising themselves specifically as a scholar, a cooper, and a fisher. At night, they will sneak into backyards and side gardens, digging up household fruits and vegetables. They pile the pilfered plants into a cart and vanish in the night. While the townsfolk wake up to empty gardens, the cultists replant the fruits in the wild to let them be "free".