Petronymphe is a monotypic genus with a very restricted range found exclusively within the state of Guerrero, Mexico. Its only known habitat is near Acahuizotla, 1 hour south of Chilpancingo at about 3500' elevation where they grow on 30 m vertical cliffs above a river. Petronymphe is member of the Brodiaea complex that also includes genera such as Dichelostemma, Triteleia and Bessera etcetera. Recent work (2001) suggests placing it in the Milla clade of a new family, Themidaceae. (This clade includes Behria, Bessera, Dandya, Jaimehintonia, and Milla).
Petronymphe decora is a species of singular beauty, crowned with a firework display of tubular yellow-green flowers arising from lax, apple-green leaves. As with Bessera, this species requires a dry winter dormancy and sharply-drained potting media. Grown in Honolulu, Hawaii. Photographs 1-5 by Jacob Uluwehi Knecht. The last photo showing the blue/indigo pollen by Colin Davis.