Holy Basil - Botanical name is Ocimum sanctum. It is known as Tulasee in Hindee in UP, Gujaraat, Mahaaraashtra, Bangaal, Tamilnaadu states of India and Arab country. It is known as Haripriyaa, Maadhavee and Vrindaa also. It has some 60 species, but four species are known very well - (1) Raamaa Tulasee, (2) Shyaamaa Tulasee, (3) Van Tulasee (Katherak), and (4) Maar Babard.

Hindu believe that Tulasee is a sacred and Divine plant. Its leaves have medicinal value. In fact not only its leaves, but its all parts have medicinal value, that is why it has a special place in our Hindu lives. Most Hindu families try to maintain at least one Tulasee plant in their homes. It contains a kind of volatile oil which has a medicinal value. If this oil is kept for sometime it is solidified and is known as Tulasee Kapoor (Tulasee camphor).

By convention, the Tulasee Leaf is not offered to Shiv, just as Bel leaves, dear to Shiv, are not offered to Vishnu. Tulasee leaves are also not offered to Lakshmee too as she was once annoyed during her love sport with Vishnu, when Vishnu's attention got diverted towards Tulasee.

Where most herbs are considered to be forms of the Goddess, Tulasee is a considered to be a Goddess herself. One legend is that a Goddess incarnated as Vrindaa and, after spending a lifetime as a very close devotee of Krishn, serves to this day as the herb Tulasee, which leads to one of Tulasee's many names, Vishnupriyaa, the beloved one of Vishnu. Her other names are Vaishnavee (Belonging to Vishnu), Vishnu Vallabhaa (Beloved of Vishnu), Haripriyaa (beloved of Hari, means Vishnu).

The Padm Puraan and Tulasee Kavach describe Tulasee as a protector of life of the human being form birth till death.

Legends About Tulasee
There are several legends about Tulasee. A number of passages in the Puraan and other scriptures (Ved), point to the importance of Tulasee within religious worship. Tulasee is regarded as Lakshmee and a consort of Vishnu. A garland of Tulasee leaves is the first offering to the Lord as part of the daily ritual. Garland of Tulasee leaves is offered in Badaree Naath Temple. Tulasee is accorded the sixth place among the eight objects of worship in the ritual of the consecration of the Kalash - the container of holy water.

(1) One legend relates that Lord Vishnu spawned Tulasee from the turbulent seas in order to help all mankind. Krishn loves Tulasee.

(2) Hindu mythological Tales narrate that Tulasee, a destitute woman, was accused of infidelity and shunned by all. Finding no shelter in the world, she turned to Vishnu for help. But the gates of Vaikunth (Vishnu's abode) were also shut on her as Vishnu's Consort Lakshmee refused to let her in. Tulasee stood in the courtyard of Vishnu's abode, under the open sky, helpless and humiliated. Her feet turned into roots, her arms sprouted leaves, and she turned into a delicate yet wild plant, her fragrance spreading all around. Lord Vishnu said - "By not abandoning her devotion to me, despite all odds, Tulasee has become my beloved, "Vishnupriyaa". She should be treated with dignity at all times - not as an unchaste woman, but as a venerable housewife, a "Sumangalee". No worship of Vishnu is complete without an offering of Tulasee sprigs. And so the Tulasee plant is nurtured in the courtyard of every house, and is identified as Vishnu's Vrindaa or Krishn's Raadhaa, women whose devotion for the Lord, though unrequited, never waned. Thus, Tulasee is seen as Lakshmee's co-wife for her unconditional devotion to Vishnu, but as Lakshmee is very jealous of her, although she resides in the home whereas Tulasee remains in the courtyard.

(3) According to one story, Tulasee was a Gopee (who was actually an incarnation of a Goddess) who fell in love with Krishn and so had a curse laid on her by his consort Raadhaa.

(4) Another story goes that Tulasee was the paramour of Lord Vishnu. Out of jealousy, Lakshmee cursed her into becoming a plant and the Lord transformed himself into the sacred Shaaligraam Stone to keep her company. The Shaaligraam is a small stone, an ammonite, a fossil genus of marine cephalopod, considered to be a natural representation of Lord Vishnu. Shaaligraam are found in the Gandakee River of Nepal. They are usually black or dark green colored, round or oval in shape, striated with tree-like markings. The curves of the striations signify the various forms / reincarnations of Vishnu. The worship of Shaaligraam doesn't involve elaborate prayer rituals. It is kept wrapped in a cloth, often bathed and perfumed. Its very presence in a home bestows health, wealth and happiness on its inhabitants.

(5) How much Tulasee is dear to Vishnu - Read A Parable About Satyabhaamaa-Tulaa Bhaar

(6) Story of Vrindaa

(7) Padm Puraan, 2/15 (p 324), says that four women came out from the sea at the time of Saagar Manthan - Lakshmee, Vaarunee, Kaamodaa, and Jyeshthaa. Lakshmee went with Vishnu as His consort. Vaarunee was the daughter of Varun Dev. Kaamodaa appeared from the wave of Amrit. She assumed the form of a tree to please Vishnu Bhagavaan and would always give pleasure to Vishnu. In this form she became known as Tulasee. Jagannaath always enjoys with her. Whoever will offer Him even one leaf of Tulasee, He will think about giving him "What can I give to him?" and He will be very pleased with him.

(8) Tulasee is mentioned in the stories of Meeraa and Raadhaa also and is immortalized in Jayadev's Geet Govind.

A Story About Tulasee
Taken from Internet

One day, Tulasee went to Vishnu and complained that she was not given the same status as Lakshmee. Both came out of Samudra (read the  Padm Puraan, 2/15 story) but He adorned Lakshmee on His chest but what honor Tulasee was given? Tulasee also has been born of Amrit then why Vishnu doesn't honor her? Tulasee was wondering. Vishnu said - "Lakshmee did penance in her previous life, that is why She has got this status. Well, Lakshmee will take birth on Prithvi and She will be the daughter of Maarkandeya Muni. You should also go on Earth and spread like a bush. Lakshmee will find shelter under your shade. I will also be born on Prithvi and then marry Lakshmee." So as per Vishnu's instruction Tulasee appeared on the banks of Kaaveree River. The whole place converted into Tulasee forest. Maarkandeya Rishi was on his pilgrimage, so he also came there wandering around and seeing beautiful environment stayed there and began to meditate. He saw Vishnu in his mind and as long as he saw Vishnu in his mind he could not see anything else around.

Now there was a child lying under the bushes of Tulasee. This child was none other than Lakshmee. In order that Maarkandeya Muni could see that child Vishnu removed His figure from Muni's mind. As Vishnu's figure disappeared from Muni's mind he opened his eyes and saw a beautiful girl lying under the shade of a Tulasee bush. He picked Her up, brought Her up like his own child and married Her to Vishnu later.

Yet Another Story
Shaaligraam or Shaaligraam Shilaa or Divine Sri Vishnu Shaaligraam - Kaalee Gandakee Muktinaath Shaaligraam in Nepal is visible Chakra on holy Lord stone. Shree Shaaligraam Shilaa is known as superior Lord Shaaligraam, according to the religious text of Devee Bhaagavat (and other scriptures). To kill demon Jalandhar, Vishnu had to destroy Satee Vrindaa's Satee Dharm. As she came to know it that she was deceived, she gave four seeming desecrations to Vishnu - to become stone, grass, tree, and plant. Vishnu accepted them and took four Avataar (incarnations). He became the stone - as Shaaligraam; the grass - as Kush; the tree - as Peepal; and the plant - as Tulasee. Since then all the four things are considered to be most auspicious to behold and to worship. So according to Shaastra Shree Shaaligraam and Tulasee had different name and types which is listed in site. Shaaligraam lives as stone in the river Kaligandakee  in  scared pilgrimage reside in Nepal.
Read more: www.nepalishaligram.doodlekit.com/home#ixzz1daVe3UJ8

Tulasee's Marriage
There is a ritual of marrying Tulasee to Vishnu in Kaarttik Lunar month. She is married to Shaaligraam. This can be performed on any day between the 11th day of Shukla Paksh and Poornimaa. Many people perform it on Prabodhinee Ekaadashee - the 11th lunar day of the bright fortnight of the Kaarttik. This festival continues for five days and concludes on the full moon day. The previous day of the marriage, Tulasee Van (a special place where Tulasee is grown in Vrindaa Van) in Vrindaa Van is decorated. Sugar cane (Gannaa) and marigold (Gandaa) flowers are offered to Vrindaa Van, Aamalaa (Indian Gooseberry) are kept at its roots. Marriage is performed in the evening. Fireworks are also displayed to mark the occasion. It is celebrated in the house also in a similar way as in Vrindaa Van