Given the descendents tested ploidy, I have doubts on the given ploidy for this rose. When I look through the examples from 'Chromosome Numbers In Rose Varieties
Book (1953)', I feel like many of them are spitballed and don't make any sense at all.

Not that this matters much at all in the grand scheme of things, but I had to pause a minute and examine this.

But if someone ever gets bored and wants to test ploidy via stomata, pollen, or root tip, this is one to try.

RHA Newsletter 8(4): 13-14 (1977)
Excerpt Canadian Rose Annual, 1976
BREEDING for WINTER HARDINESS and COLOR in ROSES
H. H. Marshall
Canada Department of Agriculture, Research Station, Morden Manitoba.

The main reason R. arkansana has not been used more often as a parent is probably because of difficulty in obtaining the first cross. There are strong interspecific sterility barriers between R. arkansana and cultivated roses but a few Floribunda roses such as 'Donald Prior' will accept R. arkansana pollen. First generation hybrids are often moderately fertile and may be crossed to sister plants or back to either parent.