Geranium robertianum vs herb roberts

Geranium robertianum and herb roberts both are nouns.

Word	Noun	Adjective	Verb	Adverb
Geranium robertianum	Yes	No	No	No
herb roberts	Yes	No	No	No

As nouns, Geranium robertianum and herb roberts are synonyms defined as:

Geranium robertianum and herb roberts: a sticky low herb with small reddish-purple flowers; widespread in the Northern Hemisphere

Other synonyms of Geranium robertianum include herb robert, herbs robert.

Geranium robertianum (noun)	herb roberts (noun)
a sticky low herb with small reddish-purple flowers; widespread in the Northern Hemisphere	a sticky low herb with small reddish-purple flowers; widespread in the Northern Hemisphere