Is it farther or further?
"plant which turns its flowers and leaves to the sun," 1620s, from French héliotrope (14c.) and directly from Latin heliotropium, from Greek heliotropion, from helios "sun" (see sol) + tropos "turn" (see trope). The word was applied c.1000-1600 in Latin form to sunflowers and marigolds. Related: Heliotropic.