Circis siliquastrum vs genus Cercis

Circis siliquastrum and genus Cercis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Circis siliquastrum	Yes	No	No	No
genus Cercis	Yes	No	No	No

Circis siliquastrum (noun)	genus Cercis (noun)
small tree of the eastern Mediterranean having abundant purplish-red flowers growing on old wood directly from stems and appearing before the leaves: widely cultivated in mild regions; wood valuable for veneers	deciduous shrubs and trees of eastern Asia, southern Europe and the United States