That is true, Fara. Henry Marshall discovered that in his seedlings back in the late 1970s. He had a seedling he called “Freckles” (not the same as the Buck variety). He said it was about 3/16 R. arkansana and (Kim–take note!) included some laxa through Prairie Princess. But with Prairie Princess it also got Suzanne, which has spinosissima ancestry with the laxa. Henry was convinced that the stippling came from R. arkansana. If I’m not mistaken, David Zlesak found a stippled R. arkansana, so it seems that arkansana is a possible source of stippling.
Peter