Yucca

This article is about the genus comprising species of perennials, shrubs, and trees. For the species of root vegetable sometimes called "yuca", see Cassava. For other uses, see Yucca (disambiguation).

Yucca is a genus of plants which are also called yucca as a common name in English. The genus is made up of 50 species native to North America from Panama to a few areas of southern Canada. The genus is generally classified in the asparagus family in a subfamily with the Agave, though historically it was part of the lily family. It has at least 50 accepted species ranging from small shrubby plants to tree like giants like the Joshua Tree.

Yucca
Yucca elata in White Sands National Park, New Mexico
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Asparagaceae
Subfamily:	Agavoideae
Genus:	Yucca L.
Species
See text
The country and state level distributions of Yucca in North America[1]
Synonyms[1]
Clistoyucca (Engelm.) Trel. Codonocrinum Willd. ex Schult. & Schult.f. Samuela Trel. Sarcoyucca (Trel.) Linding. Matuda-pina Hochstätter

The tight relationship between the yucca plants and their polinators, the yucca moths from the Tegeticula and Parategeticula genuses, is well known as an example of evolutionary mutualism. The flowers of many species are eaten as food, particularly in Central America and Mexico.

Description

Yuccas are perennial plants that have one or more rosettes of long, pointed sword shaped leaves. Usually the leaves are stiff and fibrous, but a few species have fleshy leaves.^[2] The leaves are numerous and arranged in spiral at the ends of stems or branches.^[3] Plants can be a small shrub or be large with a form like a tree.^[4] The surface of the leaves are hairless, but some have a very rough surface. About half of all species have fibers that peal off the edges of the leaves.^[5] The leaves never have spines on their edges, but sometime are very finely toothed.^[6]

Plants without stems or trunks grow from a thick underground caudex, a modified stem with growth at the end like in a palm tree.^[7] Species that do not have trunks tend to be found in colder areas such as the Rocky Mountains, Great Plains, and eastern United States. While species with trunks are more common in the subtropics, deserts, and tropics to the south.^[8] The largest of these tree yuccas is Yucca brevifolia, commonly known as the Joshua tree from the American southwest.^[9] Every species grows in soil, except for Yucca lacandonica, which grows as an epiphyte.^[10]

Some species have a scape, a long flowering stem without any leaves or bracts along its length, these are always less than 2.5 centimeters (1 in) in diameter. The inflorescence is usually upright, but in a few species bends over and hangs downward. The inflorcences can be a panicle, where the flowers are on branches off the main stem, or a raceme, where the flowers are attached directly by flower stalks to the main stem.^[2] Though the plants live for many years and flower multiple times, each inflorsecence dies after setting seed.^[10]

The flowers are large and showy, ranging from bell shaped to round like a globe.^[4] The six tepals are white to cream or slightly green in color.^[10] The tepals are thick and leathery in texture and in many species will have streaks on the three outermost in red, pink, maroon, purple, or brown.^[11]

In about half of the species the fruit is a dry capsule and for the rest it is a fleshy fruit. Inside the fruit the seeds are tightly packed, flat, and black in color.^[12] Dry capsules are held in an upright position while the soft ones hang downwards.^[4]

Due to very similar characteristics of many species it is difficult to identify them without flowers or fruits. Many characteristics taken together are needed to make identifications, often including the size and color of the pistil, style, and flowers while alive.^[13] Yuccas are distinct from Agave due to their usually less sucullent leaves, their thick flower petals, and lack of spines on leaf edges.^[6]

Taxonomy

Yucca was first described and named by Carl Linnaeus in his book Species Plantarum, published in 1753.^[1] The first work on the genus as a whole was published by George Engelmann in 1873.^[14] A lectotype for the genus, a specimen of Yucca aloifolia, was designated by Nathaniel Lord Britton and John Adolph Shafer in 1908.^[10]

In 1902 William Trelease published a paper separating out Clistoyucca and Samuela from Yucca,^[2] along with his 1893 separation of Hesperoyucca from the genus.^[15] Susan Delano McKelvey argued against this separation, though recognizing them as sections of Yucca. Though McKelvey did allow that Hesperoyucca might be recognized as a genus writing, "since a number of flower and fruit characters differ from those in all other sections." DNA investigations in the 1990s found support for Hesperoyucca.^[2] As of 2025 Hesperoyucca is listed as accepted.^[15]

Prior to the 1950s Yucca was placed in Liliaceae, the lily family, due to having a superior ovary. Since that time evidence of it being more closely related to the Agave genus has been accepted.^[16] In particular the discovery that Yucca, like plants in Agave, has 5 large and 20 small chromosomes was a large factor in reconsidering their relationship.^[17] In the APG III system, published in 2009, placed the genus into Asparagaceae in the Agavoideae subfamily.^[18] This classification continued in APG IV.^[19] However, some botanists prefer to classify this subfamily as a family named Agavaceae.^[16]

Species

As of 2025^[update] Plants of the World Online (POWO) and World Flora Online both list 50 valid species.^[1][20] In addition, POWO lists three other species, Yucca jaegeriana (McKelvey) L.W.Lenz, Yucca muscipula Ayala-Hern., Ríos-Gómez, E.Solano & García-Mend., and Yucca pinicola Zamudio,^[1] that WFO lists as unchecked or as a synonym of another species.^[21][22][23] There is also one natural hybrid, Yucca × schottii, which was formerly listed as a species under various names.^[24]

Species

Plant	Flowers	Species name	Year[25]	Range[25]
		Yucca aloifolia L.	1753	Southeastern US, Central and Southeastern Mexico
		Yucca angustissima Engelm. ex Trel.	1902	Arizona, Colorado, New Mexico, & Utah
		Yucca arkansana Trel.	1902	Arkansas, Kansas, Missouri, Oklahoma, & Texas
		Yucca baccata Torr.	1859	Southwestern US & Northern Mexico
		Yucca baileyi Wooton & Standl.	1913	Arizona, Colorado, New Mexico, & Utah
		Yucca brevifolia Engelm.	1871	Baja California Norte, western Arizona, southeastern California, southern Nevada, Sonora, & southwest Utah
		Yucca campestris McKelvey	1947	New Mexico & Texas
		Yucca capensis L.W.Lenz	1998	Baja California Sur
		Yucca carnerosana (Trel.) McKelvey	1938	Northeastern Mexico
		Yucca cernua E.L.Keith	2003	Texas
		Yucca coahuilensis Matuda & I.Piña	1980	Coahuila
		Yucca constricta Buckley	1862[26]	Texas
		Yucca decipiens Trel.	1907	Northeastern and southwestern Mexico
		Yucca declinata Laferr.	1995	Sonora
		Yucca desmetiana Baker	1870	Chihuahua
		Yucca elata (Engelm.) Engelm.	1882	Southwestern US & northern Mexico
		Yucca endlichiana Trel.	1907	Coahuila & Nuevo León
		Yucca faxoniana (Trel.) Sarg.	1905	Chihuahua, Coahuila, New Mexico, & Texas
		Yucca feeanoukiae Hochstätter	2013	Utah
		Yucca filamentosa L.	1753	Eastern United States
		Yucca filifera Chabaud	1876[27]	Northeastern, central, & southwestern Mexico
		Yucca flaccida Haw.	1819	Eastern US & Ontario
		Yucca gigantea Lem.	1859	Central America & southern Mexico[28]
		Yucca glauca Nutt.	1813	Central United States & Alberta
		Yucca gloriosa L.	1753	Southeastern United States
		Yucca grandiflora Gentry	1957	Chihuahua, Sonora
		Yucca harrimaniae Trel.	1902	Arizona, Colorado, New Mexico, Nevada, & Utah
		Yucca intermedia McKelvey	1947	Central New Mexico
		Yucca jaliscensis (Trel.) Trel.	1920	Northeastern and southwestern Mexico
		Yucca lacandonica Gómez Pompa & J.Valdés	1962	Campeche, Chiapas, Oaxaca, Tabasco, & Veracruz
		Yucca linearifolia Clary	1995	Coahuila & Nuevo León
		Yucca luminosa ined.		Northeastern Mexico[29]
		Yucca madrensis Gentry	1972	Sonora & Chihuahua
		Yucca mixtecana García-Mend.	1998	Oaxaca & Puebla
		Yucca necopina Shinners	1958	Texas
		Yucca neomexicana Wooton & Standl.	1913	Colorado, New Mexico, & Oklahoma
		Yucca pallida McKelvey	1947	Texas
		Yucca periculosa Baker	1870	Oaxaca, Puebla, Tlaxcala, & Veracruz
		Yucca potosina Rzed.	1955	San Luis Potosi & Tamaulipas
		Yucca queretaroensis Piña Luján	1989	Guanajuato, Hidalgo, Queretaro, & San Luis Potosi
		Yucca reverchonii Trel.	1911	Coahuila & Texas
		Yucca rostrata Engelm. ex Trel.	1902	Chihuahua, Coahuila, & Texas[30]
		Yucca rupicola Scheele	1850	Chihuahua, Coahuila, Nuevo León, Tamaulipas, & Texas
		Yucca schidigera Roezl ex Ortgies	1871	Baja California Norte, Arizona, California, Nevada, Sonora, & Utah
		Yucca sterilis (Neese & S.L.Welsh) S.L.Welsh & L.C.Higgins	2008	Northeast Utah
		Yucca tenuistyla Trel.	1902	Texas
		Yucca thompsoniana Trel.	1911	Chihuahua, Coahuila, Durango, Nuevo León, & Texas
		Yucca treculiana Carrière	1858	Northeastern Mexico, New Mexico, & Texas[31]
		Yucca utahensis McKelvey	1947	Northwestern Arizona, southeastern Nevada, & southwestern Utah
		Yucca valida Brandegee	1889	Baja California Norte & Baja California Sur

Names

In 1737 Linnaeus, in setting out his rules for the names of genera, wrote, "Generic names which have not a root derived from Greek or Latin are to be rejected."^[32] However, in the case of Yucca and several other names he violated his own rule by adopting names derived from other languages.^[33] The word was borrowed from the Carib language by Spanish as juca, starting with Amerigo Vespucci in 1497 referring to cassava.^[34] It was first used to refer to the unrelated plants of the Yucca genus in a German travel account published in 1557.^[10] This was used as the genus name by Linnaeus in his 1753 book Species Plantarum.^[2][1]

The name yucca is used as an English common name for plant species in the genus. It is also known as Adam's needle or as Spanish-bayonet.^[34][2] Other common names for some species include Spanish dagger, shin dagger, soapweed, or soaptree.^[34][4] The name yucca can be confused with cassava, though the spelling yuca is often used to distinguish the food from plants in Yucca.^[34]

The Aztecs living in Mexico call the local yucca species iczotl in Nahuatl, which gave the Spanish izote.^[35]

Range and habitat

The natural range of the yuccas stretches across much of southern North America from Panama in the south as far north as Alberta in Canada.^[1] The exact extent is disputed as though Yucca gigantea is listed by Plants of the World Online (POWO) and World Flora Online (WFO) as native to central America,^[1][20] other sources like World Plants list it as introduced to all the nations of Central America.^[25] Likewise, Yucca flaccida is listed as native to Onterio by POWO, WFO, and World Plants,^[1][20][25] but is listed by VASCAN as introduced.^[36]

Yuccas are generally accepted to be introduced to the islands Caribbean.^[1][20]

The yuccas are xerophytic, plants with adapations to dry enviroments, with even those native to rainy habitats growing better when in drier areas.^[37]

The smaller, freeze-tolerant species of yucca have two centers of diversity, one in Texas and other other on the Colorado Plateau. They are found generally to the north and east of the range in Chihuahuan Desert, the Trans-Pecos region, the Rocky Mountains, the Colorado Plateau, and the Great Plains. The tree like yuccas with fleshy fruits have a center of diversity in the Sonoran Desert. They are found mainly in Mexico while the tree like yuccas with spongy fruits are found only in the Mojave Desert.^[38]

Ecology

Yucca moths inside a yucca flower, Candler County, Georgia

Yuccas have a very specialized mutualistic system of pollination.^[39] Yuccca moths of in genus Tegeticula or Parategeticula pollinate the flowers and then lay their eggs in the seed capsules of yuccas.^[40] Though, the some species of Tegeticula provide no benefit to the yuccas, laying eggs but not pollinating the flowers due to lacking the specialized parts for carrying pollen.^[41] All species of yucca are polinated by at least one species of yucca moth.^[42] The mutualism was first documented by Charles Valentine Riley in 1873.^[43] This created much excitement in the scientific community. In a 1874 letter to his friend Joseph Dalton Hooker, Darwin called it, "the most wonderful case of fertilisation ever published".^[44]

Instances of animal behaviors that are exclusively aimed at polination of plants, rather than just accompanying the animal gathering food, are quite rare. Female yucca moths have tentacle-like mouth parts that they use to gather pollen and then to deposit it on the reproductive parts.^[40] In the 150 years following the discovery of this relationship it became one of the most famous of the documented plant and animal mutualisms along with the fig wasps and fig trees.^[45]

About two-thirds of the moth species are limited to just one species of yucca. There is some evidence that the moths that visit a single species are guided to the flowers by distinct scents. All yucca moths species gather together inside of blooms to mate. The females of Tegeticula gather pollen and then peirce the yucca ovaries or styles to lay their eggs. After this they deposit their load of pollen to ensure the development of seeds. The female Parategeticula moths cut groves into flower stems, petals, or other parts to lay their eggs, but also use their mouthparts to deposit pollen on stigmas and into styles.^[40] Though the reduction or local extinction of yucca moths can reduce the fertility of seeds or the numbers produced, there is not yet evidence that it reduces the populations of yuccas as they are relatively long lived.^[46]

Yucca species are the host plants for the caterpillars of the widespread but uncommon yucca giant-skipper butterfly (Megathymus yuccae), which is found across the southern United States and northern Mexico.^[47] The ursine giant skipper butterfly (Megathymus ursus), from southern Arizona, southern New Mexico, western Texas, and Nuevo León, also feeds on yuccas such as Schott's yucca (Yucca × schottii) and banana yucca (Yucca baccata). As does the more northerly Strecker's giant skipper (Megathymus streckeri), though on smaller species of yucca.^[48]

Beetle herbivores include yucca weevils, in the Curculionidae.^[49]

Uses

Yuccas are widely grown as ornamental plants in gardens.

Yucca plants have provided food and fibers to humans. Several yucca species have fleshy fruits that are edible, although the seed they contain are not. Additionally, the flowers are edible both cooked and raw and the young flowering stems of some species are edible when cooked, however others may be toxic. The leaves, roots, stems, and hearts of the plants are all toxic due to high levels of saponins.^[50]

Yucca rhizomes have been extensively used to produce soaps, shampoos, detergents and are still used to a lesser extent for this today.^[51] The leaves are still used to make trays and baskets in the southwestern US.^[52] Research efforts have been made into making use of the fibers as a substitute for sisal or abacá. However, such efforts were abandoned after conclusion of the Second World War.^[53]

Yucca extract, specifically from the rhizomes of Mojave yucca (Yucca schidigera), is also used as a foaming agent in some beverages such as root beer and soda.^[54] Yucca powder is produced from yucca plants. Harvested logs are squeezed and the sap produced is then evaporated to produce the powder used in food, cosmetics, pharmaceuticals, and as animal feed additives.^[55]

Cultivation

Very soon after the start of the Columbian exchange of plants across the Atlantic Ocean yuccas were planted in European gardens as ornamental plants with the first recorded bloom in England in 1604.^[56] Though they were planted for productive uses in Mexico prior to the Spanish Conquest, it is not recorded if they used them for ornimental purposes.^[57]

The spineless yucca (Yucca gigantea) is used as a common houseplant, though sometimes under the mistaken name of Yucca elephantipes.^[58]

Yuccas are widely grown as architectural plants providing a dramatic accent to landscape design. They tolerate a range of conditions but are best grown in full sun in subtropical or mild temperate areas.^[59] Some of the larger species of yucca are used as living barriers and fences.^[51]

Several species of yucca can be grown outdoors in temperate climates, including:^[59]

• Yucca filamentosa
• Yucca flaccida
• Yucca glauca
• Yucca gloriosa
• Yucca recurvifolia

Gastronomy

The flower petals are commonly eaten in Central America and Mexico, but the plant's reproductive organs (the anthers and ovaries) are first removed because of their bitterness.^[60][61]

In addition to being called flor de izote in Mexico yucca flowers are also called flores de palma (palm flowers) in Hidalgo and San Luis Potosí, guayas, cuaresmeñas, or chochos in Veracruz, and chochas in Tamaulipas. In central Mexico, in more rural places they are eaten as a food, as they were in pre-Hispanic times. Bunches are sold in public markets and eaten while very fresh and tender, before they become bitter. They are also cooked with scrambled eggs or in green chile salsa in this area.^[62]

Another way that yucca flowers are served is in a sauce after roasting where they are called chochos in tomachile. It is served this way as a snack or with salads in the Los Tuxtlas region of Veracruz.^[63] In the northern Mexican state of Coahuila yucca flowers are considered a traditional food for Lent.^[64]

In Mexico the fleshy fruits of some yucca species are called datiles, the same word as for the fruit of the date palm, though they are unrelated. These fruits are used to produce alcoholic drinks.^[62]

In Guatemala, they are boiled and eaten with lemon juice. In El Salvador, the tender tips of stems are eaten and known locally as cogollo de izote.^[60]

These Central American and Mexican culinary traditions have been imported to the United States to areas such as Los Angeles where the flowers of the giant yucca are eaten in season in scrambled eggs, pupusas, and tacos. Before being used as an ingredient the petals are often blanched for five minutes, though they are also eaten raw in small amounts.^[61]

Traditional uses

In rural Appalachian areas, species such as Yucca filamentosa are referred to as "meat hangers". With their sharp-spined tips, the tough, fibrous leaves were used to puncture meat and knotted to form a loop with which to hang meat for salt curing or in smokehouses.^{[citation needed]}

The dried and split trunks of yuccas are soft and work well for a hearth in starting fires via friction.^[65]

The young stalks of the soaptree yucca (Yucca elata) have been consumed by the Mescalero Apache. They are roasted over an open fire and then peeled to eat the soft interior. The flowers of the same species were frequently boiled to remove their bitter flavor or the flower pistol removed, as the most bitter part.^[50]

Symbolism

The yucca flower is the state flower of New Mexico in the southwestern United States. No species name is given in the law;^[66] however, the Secretary of State of New Mexico website notes that the soaptree yucca (Yucca elata) is one of the more widespread species in New Mexico.^[67] It was offically designated as the state flower in 1927 by the state legislature after a survey of state students with the support of the New Mexico Federation of Women’s Clubs.^[67]

The yucca, specifically Yucca gigantea, is also the national flower of El Salvador, where it is known as flor de izote.^[61] It was officially designated the floral emblem in 1995.^[68] Salvadorans often compare their ability to recover from periods of repression to the ability of the flor de izote to grow back after being cut.^[69]

Gallery

• 
  Joshua trees (Yucca brevifolia), growing in the Mojave Desert
• 
  Unknown species near Orosí, Costa Rica
• 
  Yucca near Carlsbad Caverns National Park in New Mexico
• 
  Yucca harrimaniae also known as Harriman's yucca
• 
  Yucca faxoniana in Texas, with mature fruits
• 
  Yucca schidigera in Nevada, in full bloom