bear grass vs yucca

bear grass and yucca both are nouns.

Word	Noun	Adjective	Verb	Adverb
bear grass	Yes	No	No	No
yucca	Yes	No	No	No

As nouns, yucca is a hypernym of bear grass; that is, yucca is a word with a broader meaning than bear grass:

bear grass: yucca of west central United States having a clump of basal grasslike leaves and a central stalk with a terminal raceme of small whitish flowers
yucca: any of several evergreen plants of the genus Yucca having usually tall stout stems and a terminal cluster of white flowers; warmer regions of North America

As nouns, yucca is a hypernym of bear grass; that is, yucca is a word with a broader meaning than bear grass:

bear grass: yucca of southern United States having a clump of basal grasslike leaves and a central stalk with a terminal raceme of small whitish flowers
yucca: any of several evergreen plants of the genus Yucca having usually tall stout stems and a terminal cluster of white flowers; warmer regions of North America

bear grass (noun)	yucca (noun)
stemless plant with tufts of grasslike leaves and erect panicle of minute creamy white flowers; southwestern United States and Mexico	any of several evergreen plants of the genus Yucca having usually tall stout stems and a terminal cluster of white flowers; warmer regions of North America
yucca of west central United States having a clump of basal grasslike leaves and a central stalk with a terminal raceme of small whitish flowers
yucca of southern United States having a clump of basal grasslike leaves and a central stalk with a terminal raceme of small whitish flowers
plant of western North America having woody rhizomes and tufts of stiff grasslike basal leaves and spikes of creamy white flowers