Super herb from India!
Everywhere in Indian homes there is a tulsi-matham an altar bearing a tulsi plant. In the present day apartments, many maintain a potted tulsi plant. The stem, leaves, seeds, and even the soil are considered holy. A tulsi leaf is always placed in the food offered to the Lord.
As one story goes, Tulsi was the devoted wife of Shankhachuda, celestial being. She believed that Lord Krishna tricked her into sinning. So she cursed Him to become a stone (shaaligraama). Seeing her devotion and adherence to righteousness, the Lord blessed her saying that she would become the worshipped plant, tulsi that would adorn His head. Also that all offerings would be incomplete without the tulsi leaf - hence the worship of tulsi.