Tulasi's Prayer to God
Once Tulasidevi who was born along with nectar (amrita), while churning the milky-ocean, begged Lord Narayana that she also be adorned by Him on His chest like Mahalakshmi.
Lord's boon to tulasi:
Thereupon, the Lord said that Lakshmi did very severe penance to gain a place on His chest. The Lord further said that Lakshmi would appear as Bhoomidevi at a holy place near Kumbakonam, to the south of Kaveri and would be brought up by sage Markandeya as his daughter. Tulasi should go there earlier and be in the form of lovely Tulasi plant at the sage's hermitage. Then Lakshmi would appear under the Tulasi plant as Bhoomidevi. Later on Lord Narayana would come and marry Bhoomidevi and live there forever. Then the glory of Tulasi will become known to all.
The Lord further said that those who worship Him with petals of tulasi, shall attain all prosperity in the world and also the benefit of performing 'Asvamedha yaga'. All those who reside in this holy place will attain Sri Vaikunta at the end of their lives. From then onwards, Tulasi lived in this holy place, which therefore came to be known as Tulasi Vana (Tulasi forest).