Yucca angustissima (Narrow Leaf Yucca)
Agavaceae (Agave Family)

Semi-desert, foothills. Woodlands, canyons, openings. Spring.

Linnaeus named this genus in 1753.  Why he used the word "Yucca" we do not know, but it is one of the many common names for the Manihot Plant, Cassava, Manihot esculenta, a Euphorbiaceae (Spurge Family) of the Caribbean area.  The two plants do have large tuberous roots but otherwise do not resemble each other and Linnaeus must have known this as he also named Manihot esculenta.

"Angust" is Latin for "narrow" and "issima" is a Latin suffix indicating the superlative, hence "very narrow" leaves.