Orissa, or Orissa India, is a cultivated strain of Psilocybe cubensis, one of the most popular hallucinogenic mushroom species in the world. Orissa is, indeed, from India, where it was a natural variant collected from the wild. It likes growing in elephant dung best, and can produce extremely large mushrooms. And hardly anybody seems to know anything else about it—site after site repeats those few talking points, and nothing else.
Fortunately, a lot is known about P. cubensis generally. It is usually a medium-sized gilled mushroom with a light brown cap. A partial veil covers the gills until they get close to ready to release spores. But perhaps because the species can be found over much of the world—basically, wherever mammal dung is available for the fungus to eat—it can vary a lot in shape, size, colour, and psilocybin content. Many of its cultivated strains were, like Orissa, found growing wild. Others were developed by growers. The species does have a few look-alikes, including some that are toxic, so collecting and using wild-grown mushrooms is not recommended for the non-expert.