Erica lusitanica vs true heath

Erica lusitanica and true heath both are nouns.

Word	Noun	Adjective	Verb	Adverb
Erica lusitanica	Yes	No	No	No
true heath	Yes	No	No	No

As nouns, true heath is a hypernym of Erica lusitanica; that is, true heath is a word with a broader meaning than Erica lusitanica:

Erica lusitanica: erect dense shrub native to western Iberian peninsula having profuse white or pink flowers; naturalized in southwestern England
true heath: any plant of the genus Erica

Other hypernyms of Erica lusitanica include erica.

Erica lusitanica (noun)	true heath (noun)
erect dense shrub native to western Iberian peninsula having profuse white or pink flowers; naturalized in southwestern England	any plant of the genus Erica