Botanomancy is the art of

divination Divination (from Latin ''divinare'', 'to foresee, to foretell, to predict, to prophesy') is the attempt to gain insight into a question or situation by way of an occultic, standardized process or ritual. Used in various forms throughout histor ...

by burning branches of trees or herbs. The most common branches used are

vervain ''Verbena'' (), also known as vervain or verveine, is a genus in the family Verbenaceae. It contains about 150 species of annual and perennial herbaceous or semi-woody flowering plants. The majority of the species are native to the Americas a ...

and briar. The fire and the smoke are both read to indicate which course of action should be taken.

References

Divination {{occult-stub