The Soma plant and the drink derived from the Soma, also called Soma is referenced in the Rig Veda and many of the other scriptures. This plant (and drink) find references in the Persian Avestan tradition too. Over a period of time, I think the same term started referring to a lot of different plants. Soma, the drink, is the Indian equivalent of Ambrosia – the drink of the Gods.
In the Vedas, drinking soma is said to make one happy, satisfied, and even immortal. In the modern world we live in, no one seems to have a very clear idea of which plant is actually the Soma plant. One opinion is that it is a mushroom that grows in the dark. Amanita Muscaria is one such mushroom with psychotropic properties. The book Soma: Divine Mushroom of Immortality, (Ethno-Mycological Studies) describes the Soma mushroom and the ethnic connotations in various cultures, primarily the Persian and Vedic cultures.
In modern Hindu tantric practices in the southern state of Kerala, however, Soma is a different quantity. The botanical name of Soma is `Sarcostemma Brevistigma`. It is a creeper(vine) that is commonly found in the Western Ghats of South India. The stem is used to make the Somarasa for many yagas in Kerala. The King of Kollengode, an erstwhile principality in Kerala, is obliged to supply the soma stems for yagas. It is described in the book Agni by Frits Stall.
The search for the Soma plant continues — if someone were to find it, as described in the Veda and the Avesta, it would bestow immortality, the light of knowledge/awareness, and heal many ills(according to Susrutha and the Atharva Veda). In later Hinduism the Soma was replaced by the Rhubarb plant due to Soma being unavailable. Susrutha also mentions that the best Soma can be found in Kashmir and the Upper Indus region.
There is also a mythological god Soma, who was depicted as a bull or bird, and sometimes as an embryo. What is interesting is that he is never shown as a mature adult. In Hinduism, the god Soma evolved into a lunar deity, and became associated with the underworld. The moon is the cup from which the gods drink Soma, and so Soma became identified with the moon god Chandra. This explains why in Hindi, “Somvar” means “Monday”. A waxing moon meant Soma was recreating himself, ready to be consumed. Soma had twenty-seven wives all of whom were daughters of the great King Daksha (the Daksha who conducts the Daksha yaga, father of Dakshayani or Parvati), who felt he paid too much attention to just one of his wives, Rohini (the star). He cursed him to wither and die. His wives would have none of that and so they intervened and the death became periodic and temporary. Soma is perpetually condemed to die and be reborn once every 28 days.
To add to the confusion, there is a drug called Soma, and some contend that Soma is nothing but the common Marijuana plant. I find the concept of Soma very alluring – does it suggest that the ancients had knowledge of hallucinogenics, and the “awakening” they speak of is the same as Huxley’s Doors of Perception being opened wide?