wild cotton vs cotton plant

wild cotton and cotton plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild cotton	Yes	No	No	No
cotton plant	Yes	No	No	No

As nouns, cotton plant is a hypernym of wild cotton; that is, cotton plant is a word with a broader meaning than wild cotton:

wild cotton: shrub of southern Arizona and Mexico
cotton plant: erect bushy mallow plant or small tree bearing bolls containing seeds with many long hairy fibers

Other hypernyms of wild cotton include cotton.

wild cotton (noun)	cotton plant (noun)
shrub of southern Arizona and Mexico	erect bushy mallow plant or small tree bearing bolls containing seeds with many long hairy fibers