Crystilia are flowering plants native to Telemarius IV. Crystilia blossoms produce a fragrance pleasant to Humans, which is a biochemical response to the acrid atmosphere of their native planet.

Lieutenant Commander Data presented a bunch of crystilia to Lieutenant Jenna D'Sora in 2367, when the two were "dating". Data's choice came from Commander William Riker's recommendation, since crystilia had "worked for him before". (TNG: "In Theory")