Grindelia robusta vs gumweed

Grindelia robusta and gumweed both are nouns.

Word	Noun	Adjective	Verb	Adverb
Grindelia robusta	Yes	No	No	No
gumweed	Yes	No	No	No

As nouns, gumweed is a hypernym of Grindelia robusta; that is, gumweed is a word with a broader meaning than Grindelia robusta:

Grindelia robusta: perennial gumweed of California and Baja California
gumweed: any of various western American plants of the genus Grindelia having resinous leaves and stems formerly used medicinally; often poisonous to livestock

Other hypernyms of Grindelia robusta include gum plant, rosinweed, tarweed.

Grindelia robusta (noun)	gumweed (noun)
perennial gumweed of California and Baja California	any of various western American plants of the genus Grindelia having resinous leaves and stems formerly used medicinally; often poisonous to livestock