Indian madder (Rubia cordifolia); a perennial climbing herb with a square stem, small yellow flowers, and heart-shaped leaves. Its roots are used for red dye and in traditional medicine.

A red crystalline compound used as a dye, originally extracted from madder root but now synthesized chemically.

Eryngium foetidum; a tropical perennial herb also known as Mexican coriander or long coriander

(literary) madder, a plant used as a source of red dye