Druid

Preparation

A druid is a preparation spellcaster that casts divine spells drawn from the druid spell list. His alignment, however, may restrict him from casting certain spells opposed to his moral or ethical beliefs; see Chaotic, Evil, Good, and Lawful Spells in the core rules.

Spell Availability

A druid may cast any spell he is attuned to based on the Attunement table, as long as he has the Anima Points to do so. To attune to or cast a spell, a druid must have a Wisdom score equal to at least 10 + the spell level.

Spell DC

The Difficulty Class for a saving throw against a druid’s spell is 10 + the spell level + the druid’s Wisdom modifier.

Anima Points

A druid has a number of APs in a spell pool. The druid's APs are defined by the Druid's Anima Points per level table below, plus any bonus anima points based on the Bonus Anima Points table,

Burned Aura

Because a druid’s spells are not internalized to his aura (they are sacred powers cast through divine inspiration, each time the druid casts a spell it leaves some traces on his magic aura (much like the lingering auras that can be revealed with a detect magic spell, though the residue on a druid’s aura is often too faint to actually set off detect magic).

This residue, known as Burned Aura, makes it difficult for the druid to cast the same spell multiple times in the same day, as some traces of its previous mystic pattern interfere with the casting process. As a result, each time a druid casts the same spell since restoring his spell pool, It costs one additional AP each time the same spell is cast.. (Though see Spontaneous Casting, below.) This additional spell-point cost is removed when the druid refills his spell-points and attunes his spells for the day.

Spontaneous Casting

A druid can channel AP into summoning spells without incurring Casting Fatigue. The druid is automatically considered attuned to all “summon nature’s ally” spells, and when the druid casts such spells, the AP cost of the spell does not increase.

Recuperation

A druid must spend 1 hour each day in a trance-like meditation on the mysteries of nature to regain her daily allotment of spells. A druid may prepare and cast any spell on the druid spell list, provided that she can cast spells of that level, but she must choose which spells to prepare during her daily meditation.

References

https://www.d20pfsrd.com/classes/core-classes/druid/