Tulsi / तुलसी
It is a small plant which is believed to be very pure and its leaves are used during the worship. It is grown in the courtyard of the house. It is watered in the evening and a diya is lit under it in the evening. Puranas have a story about tulsi.
Tulsi was a friend of Radha but Radha cursed her. She was born in Dharamdhwaj's family. She was very beautiful and pleased Brahma with her penance. She wished Vishnu to be her husband. But she got married to Shankchurna, a demon. He had the boon that he cannot die until his wife's faithfulness is dissolved. When Shankhchurna became very troublesome, Vishnu dissolved Tulsi's faithfulness by taking her husband's form. Filled with anger, Tulsi cursed Vishnu to turn into a stone. But Vishnu gave her a blessing that a plant named tulsi will rise from her hair and she will be dear to him just like Lakshmi. Since then Vishnu is offered tulsi leaves.
Tulsi's other name is Vrinda. Vrindavan is named after her name.