Fagus pendula vs beech tree

Fagus pendula and beech tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Fagus pendula	Yes	No	No	No
beech tree	Yes	No	No	No

As nouns, beech tree is a hypernym of Fagus pendula; that is, beech tree is a word with a broader meaning than Fagus pendula:

Fagus pendula: variety of European beech with pendulous limbs
beech tree: any of several large deciduous trees with rounded spreading crowns and smooth grey bark and small sweet edible triangular nuts enclosed in burs; north temperate regions

Other hypernyms of Fagus pendula include beech.

Fagus pendula (noun)	beech tree (noun)
variety of European beech with pendulous limbs	any of several large deciduous trees with rounded spreading crowns and smooth grey bark and small sweet edible triangular nuts enclosed in burs; north temperate regions