Does "California Blackberry" Exist?

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What is the proper course of action when you come across a species that likely doesn’t exist?

Observations of Rubus ursinus macropetalus or “California Blackberry” seem to all be Rubus ursinus, Rubus bifrons, or a hybrid of the two. The native Rubus ursinus does readily hybridize with invasive R. bifrons.

Flora of North America Vol 9 (which refers to a “Rubus macrophyllus”) could not find a single specimen in their 2015 revision:

“Specimens examined for this study of North American collections attributed to Rubus macrophyllus Weihe & Nees (synonym R. amplificatus Lees) are R. ursinus. If R. macrophyllus was once present in the flora area it is likely absent now; some reports of R. macrophyllus could represent hybrids. There are reports of R. ursinus hybridizing with R. bifrons and R. pensilvanicus in California (T. S. Mallah 1954; L. V. Clark and M. Jasieniuk 2012; L. A. Alice, unpubl.).”

Rubus has been challenging for me to wade through as a whole: I know this is not a new topic. But in this case, I feel like I have come upon a colloquial term in “California Blackberry” that has co-opted a 1913 description of Rubus ursinus.

What would you do with these observations?

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You might consider asking Mark Widrlechner of Iowa State University about this one. He’s a Rubus expert.

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Very good - After posting, I found a very similar discussion linked in the comments of a “California Blackberry” observation:

Rubus ursinus macropetalus · iNaturalist

@graysquirrel noted that 2 years ago they would “add a flag to the taxon and see if anyone wants to change it.” - I am uncertain about flags. I wonder if any progress was made on this.

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For what it’s worth, the flag discussion is here: https://www.inaturalist.org/flags/598151 Probably best to continue the discussion there

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Thanks, I did post to the flag. I’m new to flags in general–appreciate your link.

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