Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Asparagaceae
Subfamily: Agavoideae
Genus: Hesperoyucca
Species: H. whipplei
Binomial name: Hesperoyucca whipplei
Synonyms: Yucca whipplei, Yucca californica, Yucca graminifolia, Yucca nitida, Yucca whipplei ssp. caespitosa, Yucca
hipplei ssp. eremica, Yucca whipplei ssp. intermedia, Yucca whipplei ssp. parishii, Yucca whipplei ssp. percursa, Yucca whipplei var. caespitosa, Yucca whipplei var. graminifolia, Yucca whipplei var. intermedia, Yucca whipplei var. parishii, Yucca whipplei var. percursa, Yucca whipplei var. whipplei
Common name: Our Lord's candle, Chaparral yucca, Spanish bayonet, Quixote yucca, Foothill yucca.

Hesperoyucca whipplei is a species of a flowering plant closely related to a yacca and formerly was included in the genus Yucca. It is native to central California east to extreme south-west Arizona and south into Baja California where it occurs mainly in chaparral, coastal sage scrub, and oak woodland plant communities at altitudes of 0–2500 m.
Hesperoyucca whipplei is a dense rosette-forming plant with rigid, stemless, silver-grey leaves that are margined yellow or brown and have a very sharp tip. The leaves are >90 cm (rarely >125 cm) long and are >2 cm wide with edges that are finely saw-toothed.
Hesperoyucca whipplei usually after 5+ years reaches maturity and then during mid-spring to summer it flowers and then it usually dies. Flowering occurs as a single a stout stalk which grows extremely fast and will reach a height of 0.9–3 m.
The flowering spike bears hundreds of 3 cm diameter, drooping, fragrant, bell-shaped creamy-white flowers that are sometimes tinged with purple. The densely branched panicle is >70 cm broad and covers the upper half of the spike.
The fruit is a dry winged capsule, which splits open at maturity to release the seeds.

Hesperoyucca whipplei in flower at the Christchurch Botanical gardens early November. It flowers once then dies.
Hesperoyucca whipplei Our Lord s candle -001.JPG

Hesperoyucca whipplei Our Lord s candle -002.JPG 

Hesperoyucca whipplei Our Lord s candle -003.JPG  

A single open flower.
Hesperoyucca whipplei Our Lord s candle -004.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/