Ledyard Stebbins Gave us Ehrharta

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.

由使用者 kueda kueda2021年11月27日 05:05 所貼文


Wow! I clicked on the link and was surprised that it is not tagged as non-native or invasive. How can that be remedied?

發佈由 alexia-s 超過 2 年 前

You mean Stebbins Grass? :) He even planted it up in the White Mountains at Crooked Creek Field Station. I have several friends who knew Ledyard and spent a fair amount of time with him in the 70s and 80s when he was working to get CNPS chapters going around the state by giving talks and field trips. If you haven't read his 1965 paper with Jack Major, Endemism and Speciation in the California Flora, I recommend it. Amazing piece.

發佈由 randomtruth 超過 2 年 前

@alexia-s, as far as I can tell it is marked as "introduced" in California on iNat, though maybe someone did that after you commented?

@randomtruth, I missed the bit about the White Mountains if that was in that paper. Wild. Do you know if he ever expressed guilt about spreading it all around the state?

發佈由 kueda 超過 2 年 前

Apologies for the slow reply, Ken-ichi. From what I understand, the idea that Stebbins was the source of the spread is likely over-stated. As you note, he spotted it on the Berkeley campus as it was likely already spreading. And I've heard the suspected vector is more likely planting/potting soil in the nursery trade, coinciding with the rise in use of South African cultivars and the expansion of suburbia.

發佈由 randomtruth 超過 2 年 前


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