Darwin called the yucca and its moth the most wonderful pollination known
A female yucca moth does something few animals do: she pollinates on purpose. Using tentacle-like mouthparts, she gathers pollen, packs it onto a yucca flower's stigma and then lays eggs in the developing seed capsule. Darwin, hearing of it in 1874, rated it the most marvellous account of fertilisation yet in print.
The partnership was first described by Charles Valentine Riley in 1873 and ranks with the fig and its wasps among the best-known alliances between plants and animals. Molecular clocks suggest it began between about 51 and 32 million years ago. Nearly every yucca depends on one or more moth species, though some cheating moths lay eggs without carrying any pollen. One species, the aloe yucca, switches to general pollinators where its moths are missing.
Yucca holds 50 accepted species native from Panama to southern Canada, now grouped in the asparagus family alongside Agave. Before the 1950s botanists filed them with lilies, but the discovery that yuccas share Agave's set of 5 large and 20 small chromosomes changed minds. All have rosettes of pointed, sword-shaped leaves without edge spines, and tall stalks of thick, cream-white flowers. Stemless kinds dominate colder areas such as the Great Plains and Rockies, while trunked species prefer the warmer south. The largest, the Joshua tree, grows up to 15 metres tall.
The name has a tangled history. Linnaeus had ruled that genus names should come from Greek or Latin, yet he broke his own rule for this one. Spanish had borrowed juca from Carib for cassava, a use recorded from Amerigo Vespucci in 1497; a German travel account applied it to these unrelated plants in 1557. Cooks still write yuca for the root crop to avoid confusion. Aztecs called the local plants iczotl, the source of the Spanish izote.
People in Mexico and Central America eat the petals, and the plants were once a major source of fibre for cord, baskets, mats and sandals. Native peoples still make soap from them. Yuccas have also escaped gardens as far away as Poland, Pakistan and Australia.
Source: Yucca
