Mostly a note to myself so I don't forget, but today Janet Gawthrop told me Ehrharta erecta became invasive in California because of a research project at UC Berkeley investigating the effects of ploidy on adaptation. Investigating later, I was rather horrified to learn that Ledyard Stebbins intentionally mutated these plants to create tetraploid versions and intentionally planted both diploid and tetraploid plants in the hills above UC Berkeley, in Napa, and near Monterey in a multi-decade study starting in the 1940s. His papers don't seem to mention any kind of containment or eradication strategy, so it seems likely that his efforts led directly to the rather extreme invasion of this plant we have to deal with in coastal CA today. The tetraploids died off, but the diploids flourished.
A note in the 1949 paper suggests it might have already been established on the UC Berkeley campus before the study began:
The artificial autotetraploid of E. erecta, produced from plants spontaneous on the University of California campus, is taller, coarser, and has fewer tillers than its diploid progenitor (Fig. l)
But still, Ledyard, way to screw over vast swaths of California native plants in the name of science.
