The Indian Soma and the Persian Haoma of the Zoroastrians are related. Some schools claim that they were identical. Others insist that they were quite distinct.

One school identifies Haoma with the plant Ephedra. Others claim that haoma sometimes included mixtures with cannabis or opium.

The recipes for the two parahaoma preparations, though not identical, are largely the same. In both cases, the ingredients include three small haoma twigs; consecrated water; twigs and leaves from a pomegranate tree. The second parahaoma also includes milk (in Iran from a cow, in India from a goat).
Wikipedia: ab-zohr

The Indian Tree, or Tree of Life pattern is the most vitally interesting of all artistic designs. The first Tree of Life known to symbolism was a plant called hom. "The original HOM was the Sanscrit Soma . . . . a leafless (the rudimentary leaves are scarcely visible) scadent asclepiad, with its flowers collected in umbels, fan-like in silhouette ...a native of the southern slopes of the Cashmere Valley and Hindu Kush."