Yucca

Scientific

Yucca (family Asparagaceae) contains ~50 species across North America, Central America, and the Caribbean. Principal species:

• Yucca brevifolia — Joshua tree; Mojave Desert; the giant tree yucca with the iconic silhouette
• Yucca elata — soaptree yucca (pictured); [[sonoran-desert|Sonoran]] and Chihuahuan deserts
• Yucca filamentosa — Adam’s needle; widely planted ornamental
• Yucca aloifolia — Spanish bayonet; common in the southeastern US
• Yucca gloriosa — Spanish dagger; East Coast US, naturalized in Europe

The taxonomic name confusion: yucca (the desert plant, genus Yucca) should not be confused with yuca ([[cassava|cassava]], Manihot esculenta, the South American starchy root). The two share a similar-sounding common name but are entirely unrelated.

Yucca-moth coevolution

Each yucca species is pollinated by one or a few specific moth species in the family Prodoxidae (genus Tegeticula mostly). The moth deliberately collects yucca pollen, transfers it to another yucca flower’s stigma, and lays eggs in the developing fruit. The moth larvae feed on some of the developing yucca seeds; the rest mature and disperse the species. Without the specific moth species, the yucca cannot reproduce; without the yucca, the moth cannot reproduce.

The relationship is one of the textbook examples of obligate plant-pollinator coevolution — and one of the earliest scientifically documented (Charles Valentine Riley, 1872). The fig-and-fig-wasp system covered under [[fig]] is structurally similar but evolved entirely independently.

Cultural and economic

The Joshua tree is the visual signature of the Mojave Desert and the namesake of Joshua Tree National Park. The species is currently threatened by climate change — projected Mojave warming and drying may eliminate most of the species’ viable range within decades. Joshua tree dieback has accelerated in recent severe-fire years.

Native American (especially Mojave, Cahuilla, and Chemehuevi) traditional uses of yucca include fiber (basketry, sandals, rope), soap (the roots contain saponins that lather in water), and food (the flower stalks, fruits, and seeds of several species are edible).

See also

Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.

• Shares approach with: [[fig]]
• Member of: [[plants]]

Sources

• Wikipedia — Yucca

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A plant entry in the 0mn1.one [[directory]].