corn salad vs herbaceous plant

corn salad and herbaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
corn salad	Yes	No	No	No
herbaceous plant	Yes	No	No	No

As nouns, herbaceous plant is a hypernym of corn salad; that is, herbaceous plant is a word with a broader meaning than corn salad:

corn salad: a plant of the genus Valerianella
herbaceous plant: a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

Other hypernyms of corn salad include herb.

corn salad (noun)	herbaceous plant (noun)
a plant of the genus Valerianella	a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests