Asat (Sanskrit) [from a not + sat being from the verbal root as to be] Not being, non-being; used in the Indian philosophies with two meanings almost diametrically opposed: firstly, as the false, the unreal, or the manifested universe, in contrast with sat, the real; secondly, in a profoundly mystical sense, as all that is beyond or higher than sat. "Sat is born from Asat, and Asat is begotten by Sat: the perpetual motion in a circle, truly; yet a circle that can be squared only at the supreme Initiation, at the threshold of Paranirvana" (SD 2:449-50). In its lower sense, asat signifies the realms of objective nature built out of and from the various prakritis, and therefore regarded as illusory in contrast to the enduring Be-ness or sat. In its higher sense asat is that boundless and eternal metaphysical essence of space out of which, in which, and from which even sat or Be-ness itself is and endures. Asat here is parabrahman-mulaprakriti in its most abstract meaning.
-From the Sanskrit Dictionary. The tree is called: ashvattha.