Among the various plants meant for divine worship, Thulasi plant is one. The devi who does patha sevanam to maha Vishnu is also called Thulasi. Thulasi is also called Vishnupriya. One should not touch Thulsi without taking bath. Manikandan is wearing mala made out of the barks of the thulasi plant and is known as thulasi mani marban. Just to show the intense and pure bhakthi only, the habit of wearing thulasi malai for going to sabarimalai was started. Ayyappan is a form of Vishnu. His mother is  Mohini another form Vishnu. As is mother so is the child. Like that thulasi which was liked by Vishnu was also liked by ayyappan.