lemonweed

from The Century Dictionary.

• noun In the southwestern United States, Pectis filipes, P. papposa, and P. longipes, small yellow-flowered lemon-scented composites with linear leaves dotted with oilglands. These plants are used medicinally by the Indians and the white settlers, in the form of a decoction. See limoncillo, 2.
• noun A sea-mat of the family Flustridæ: so called from its scent.