While related to the more well-known Ocimum basilicum, the basil used in cooking, Holy Basil is a medicinal herb used to make teas and extracts. It's known as a sacred plant in India.
The Rama and Krishna varieties share the interchangeable botanical names Ocimum tenuiflorum and Ocimum sanctum; the two Latin names are synonymous with each other. They are, however, more like fraternal twins: The Rama variety is a short, annual, heavily flowered plant originally introduced to the U.S. as "Holy Basil". It is the most common type found in cultivation in the U.S. and is known for its cooling and mellow flavor and makes a delicious tea.
Botanical Name: Ocimum tenuiflorum/Ocimum sanctum (Rama & Krishna),
Common Name: Holy Basil, Tulsi 
Warning Holy Basil Leaf, Rama & Krishna (Ocimum tenuiflorum/Ocimum sanctum): Holy Basil may modify glucose regulation.
California Proposition 65 WARNING