Yucca gloriosa, also known as Spanish dagger, mound lily yucca and other common names, is a species of flowering plant in the asparagus family, native to the southeastern United States. Growing to , it is an evergreen shrub. It is widely cultivated as an ornamental for its architectural qualities, and has reportedly become established in warmer climates in the wild in various parts of the world.

 Yucca gloriosa is caulescent, usually with several stems arising from the base, the base thickening in adult specimens. The long narrow leaves are straight and very stiff, growing to long and wide. They are dark green with entire margins, smooth, rarely finely denticulate, acuminate, with a sharp brown terminal spine. The inflorescence is a panicle up to long, of bell-shaped white flowers, sometimes tinged purple or red. The fruit is a leathery, elongate berry up to 8 cm long.

Taxonomy: Yucca gloriosa was first described by Carl Linnaeus in 1753. Genetic evidence has shown that the species originated via multiple hybridizations between Yucca aloifolia and Yucca filamentosa. It is classified as part of the Yucca genus within the Asparagaceae family.

The species has two accepted varieties:

• Yucca gloriosa var. gloriosa
• Yucca gloriosa var. tristis

Yucca gloriosa has synonyms of the species or one of its two varieties including 28 species.

Table of Synonyms	Name	Year	Rank	Synonym of:	Notes
Haw.}}	1812	species	var. tristis	= het., nom. illeg.
Sweet}}	1827	species	var. gloriosa	= het.
Truff.}}	1869	species	var. gloriosa	= het.
Carrière}}	1859	species	var. tristis	= het., nom. illeg.
Baker}}	1870	species	var. tristis	= het.
Baker}}	1872	species	var. gloriosa	= het.
Groenland}}	1858	species	var. gloriosa	= het.
Baker}}	1880	species	var. tristis	= het.
Anon.}}	1876	species	var. tristis	= het.
(Baker) Baker}}	1880	variety	var. tristis	= het.
Carrière}}	1859	species	var. tristis	= het.
(Baker) Trel.}}	1902	form	var. tristis	= het.
(Groenland) Voss}}	1895	form	var. gloriosa	= het.
(Groenland) Baker}}	1880	variety	var. gloriosa	= het.
(Anon.) Baker}}	1880	variety	var. tristis	= het.
Trel.}}	1902	form	var. tristis	= het.
(André) Trel.}}	1902	form	var. gloriosa	= het.
(Baker) Trel.}}	1902	form	var. tristis	= het.
Trel.}}	1902	form	var. tristis	= het.
(Baker) Trel.}}	1902	form	var. gloriosa	= het.
(Sweet) Voss}}	1895	form	var. gloriosa	= het.
(Sweet) Carrière}}	1868	variety	var. gloriosa	= het.
Carrière}}	1880	variety	var. tristis	= het.
(Baker) Baker}}	1880	variety	var. gloriosa	= het.
(Carrière) Trel.}}	1902	variety	var. tristis	= het.
Engelm.}}	1873	form	Y. gloriosa	≡ hom., not validly publ.
Carrière}}	1860	variety	var. gloriosa	= het.
Carrière}}	1862	variety	var. gloriosa	= het.
(Carrière) Trel.}}	1902	form	var. gloriosa	= het.
Carrière}}	1859	variety	var. gloriosa	= het.
(Carrière) Trel.}}	1902	form	var. gloriosa	= het.
Carrière}}	1880	variety	var. tristis	= het.
Carrière}}	1880	variety	var. tristis	= het.
Carrière}}	1880	variety	var. gloriosa	= het.
Planch.}}	1880	variety	var. gloriosa	= het.
(Planch.) Trel.}}	1902	form	var. gloriosa	= het.
Carrière}}	1860	variety	var. gloriosa	= het.
(Carrière) Trel.}}	1902	form	var. gloriosa	= het.
Carrière}}	1860	variety	var. tristis	= het.
Carrière}}	1860	variety	var. gloriosa	= het.
(Carrière) Trel.}}	1902	form	var. gloriosa	= het.
(Haw.) Baker}}	1870	variety	var. gloriosa	= het.
(Haw.) Voss}}	1895	form	var. gloriosa	= het.
Carrière}}	1860	subvariety	var. gloriosa	= het.
(Groenland) Schelle}}	1903	form	var. tristis	= het.
Engelm.}}	1873	variety	var. tristis	= het.
Carrière}}	1860	variety	var. gloriosa	= het.
(Baker) Baker}}	1880	variety	var. gloriosa	= het.
(Baker) Voss}}	1895	form	var. gloriosa	= het.
Baker}}	1870	variety	var. gloriosa	= het.
(Salisb.) Engelm.}}	1873	variety	var. tristis	= het.
Carrière}}	1860	variety	var. gloriosa	= het.
(Haw.) Baker}}	1880	variety	var. tristis	= het.
(Haw.) Voss}}	1895	form	var. tristis	= het.
Baker}}	1870	var. gloriosa	variety	= het.
(Baker) Trel.}}	1902	form	var. gloriosa	= het.
(Baker) Baker}}	1880	variety	var. gloriosa	= het.
(Baker) Voss}}	1895	form	var. gloriosa	= het.
(Carrière) Carrière}}	1880	variety	var. tristis	= het.
Sprenger}}	1904	species	var. tristis	= het.
Stokes}}	1812	species	var. gloriosa	= het.
Carrière}}	1859	species	var. tristis	= het.
Carrière}}	1859	species	var. tristis	= het., nom. illeg.
Haw.}}	1812	species	var. gloriosa	= het.
André}}	1870	species	var. gloriosa	= het.
Baker}}	1880	species	var. tristis	= het.
Groenland}}	1858	species	var. tristis	= het.
Carrière}}	1877	variety	var. tristis	= het.
Carrière}}	1875	variety	var. tristis	= het.
(Carrière) K.Koch}}	1873	species	var. gloriosa	= het.
K.Koch}}	1873	species	var. gloriosa	= het.
Baker}}	1870	species	var. gloriosa	= het.
Haw.}}	1812	species	var. tristis	= het.
Salisb.}}	1806	species	var. tristis	= het.
(Carrière) Trel.}}	1902	form	var. tristis	= het.
(Carrière) Trel.}}	1902	form	var. tristis	= het.
(Haw.) Baker}}	1870	variety	var. tristis	= het.
(Haw.) Trel.}}	1902	form	var. tristis	= het.
(Carrière) Trel.}}	1902	form	var. tristis	≡ hom.
(Carrière) Trel.}}	1902	form	var. tristis	= het.
Haw.}}	1819	species	var. tristis	= het.
Baker}}	1870	species	var. tristis	= het.
Carrière}}	1859	species	var. tristis	= het.
Haw.}}	1819	species	var. gloriosa	= het., nom. illeg.
Baker}}	1870	species	var. gloriosa	= het.
Notes: ≡ homotypic synonym; = heterotypic synonym

Names: In addition to Spanish dagger and mound lily yucca, Yucca gloriosa is also commonly known as Roman candle, palm lily, and Spanish needle. However all of these names are ambiguous, with Roman candle also referring to Senna alata or a trade name for a Podocarpus macrophyllus cultivar, palm lily almost always referring to Cordyline fruticosa or other Cordylines, and Spanish needle also referring to Bidens alba.

In the horticultural trade, Yucca gloriosa var. tristis varieties, with their less rigid leaves, are often referred to as Y. pendula or Y. recurvifolia, and commonly called soft-leaf (or soft-tipped) yucca, weeping yucca, curve-leaf yucca or curved-leaved Spanish-dagger.

Habitat: Yucca gloriosa grows on exposed sand dunes along the coast and barrier islands of the lower East Coast of the United States, often together with Yucca aloifolia and a variety formerly called Yucca recurvifolia or Y. gloriosa var. recurvifolia, now Y. gloriosa var. tristis. Large, endemic populations can be found in the beach and dune environments of coastal North Carolina. In contrast to Y. gloriosa var. tristis, the leaves of Y. gloriosa var. gloriosa are hard stiff, erect and narrower. On the other hand, Y. aloifolia has leaves with denticulate margins and a sharp-pointed, terminal spine.

Distribution: Yucca gloriosa is native to the coast and barrier islands of southeastern North America, growing on sand dunes. It ranges from extreme southeastern Virginia south to northern Florida in the United States. It is associated with Yucca filamentosa, Yucca aloifolia, and Opuntia species.

Cultivation: The plant is widely cultivated in warm temperate and subtropical climates, and valued as an architectural focal point. It has reportedly escaped from cultivation and naturalised in Italy, Turkey, Mauritius, Réunion, Guam, the Northern Mariana Islands, Puerto Rico, Argentina, Chile and Uruguay.
In landscape use, little maintenance is needed other than the removal of dead leaves when the shrub nears its ultimate height. The plant is very hardy, without leaf damage at , and can handle brief snow and freezing temperatures, as well as long periods of drought.

Yucca gloriosa, and the cultivars ´Variegata´ and = ´Walbristar´ have gained the Royal Horticultural Society´s Award of Garden Merit.

Properties: Yucca gloriosa has been known to cause skin irritation and even allergic reactions upon contact. The leaf points are even sharp enough to break the skin.