The book Compendium of Natural Magic with Tatyana's Flowers presumably besides it.
Tatyana's Flowers are a special type of plant that has red flowers and is normally indistinguishable from a typical Potted Plant. They are named after Tatyana Yokobik, an archemage who supposedly used these plants as a means of "temporary negation of magical spells and systems".
According to chapter 15 of the book "Compendium of Natural Magic", these flowers are native to the Esse Range; a frigid mountainous terrain. In order to survive, they have special properties that enable them to diffuse Magic and to induce sleep. The nature of these abilities are unclear, but have been attributed to the "warming and swirling [of] the magical energy of the sentient plants and rocks".[1]
In-Game[]
Only three potted plants in Constantine's bedroom can be confidently identified as Tatyana's flowers, one because of its proximity to the Compendium of Natural Magic, which is right besides it, and two others because they are on opposite sides of Constantine's bed in the same room.[2]