Nityananda! Gauranga! Hare Krishna! Jaya Guru Parampara! :pranams: Pranams! There are two types of Tulasi plants. One, grown in direct sunlight, develops purple leaves and stems, and dark purple to pink flowers which is called a Krishna Tulasi. The other, whose leaves and stems never turn purple and whose flowers are pure white, is called a Raama Tulasi.
Tulasi's Latin name is Ocimum sanctum L. Ocimum means she is related to the basil herb, and sanctum means "holy." Thus she is also known as the "Holy Basil." There is also a Lakshmi Tulasi or Tulasa. She is a tree basil and her Latin name is Ocimum gratissmum var. suave (Wild) Hook f. In worship, she is used as a substitute when Tulasi is not available.
Whoever cultivates and cares for a Krishna or Raama Tulasi plant purifies oneself, gives pleasure to Lord Gauranga Krishna, and obtains Tulasi Devi's mercy, namely, devotional service to and pure love of Gauranga Krishna. Both Krishna and Raama Tulasi leaves can be offered to the Lord as there is no such discrimination found in the scriptures. The soft Tulasi manjaris are the most pleasing to the Lord along with Tulasi leaves.