Word: turnsole
The heliotrope; so named because its flowers are supposed to turn toward the sun.
The sunflower.
A kind of spurge (Euphorbia helioscopia).
The euphorbiaceous plant Chrozophora tinctoria.
A purple dye obtained from Chrozophora tinctoria.
Litmus
You can find a list of possible crossword clues for TURNSOLE below.