It follows that if the Rosa foliolosa in commerce since at least 1890 is an imposter, then all hybrids from it would not be true foliolosa either. There are only two I know of, ‘Basye’s Purple’ and ‘Ann Endt’.
Dr. Robert Basye, Professor of Mathematics at Texas A.& M. University also hybridized roses and created ‘Basye's Purple’ in 1968. He reported this hybrid as pollen of Rosa rugosa rubra crossed with seed parent Rosa foliolosa (2n=14). The resulting Rose was full of drama, with pallid foliage, dark brooding canes and flowers having a funeral aspect like their petals were cut from some purple velvet shroud, truly an American Gothic rose!
The rugosa rubra in its parentage was obvious in leaf texture, dark very prickly canes and flower color and size. But where was foliolosa? Nowhere that I could find but there was one clue to the other parent. ‘Basye’s Purple’ has curled, tubular stipules. So Rosa palustris (2n=14 or 28) or some palustris hybrid was the seed parent. Likely, Basye’s seed parent was the foliolosa imposter that’s been around for at least 130 years. Some form of palustris which I’ve named “Hilliers Foliolosa” because that’s where my plant originated via Pat Cole, past Editor of The Rose Letter.
The Canadian hybridizer, Percy Wright reported he received a plant of Rosa foliolosa from “a Texas mathematician” but whether he hybridized with it I don’t know.
The other Rosa rugosa x foliolosa hybrid ‘Ann Endt’ was discovered in New Zealand, given to Nancy Steen author of The Charm of Old Roses as an unknown foliolosa. Nancy already had the true Rosa foliolosa Nuttall ex Torrey & Gray growing in her garden and this was not the same. So she thought it was possibly M. Maurice Vilmorin’s rugosa x foliolosa hybrid illustrated in Les Plus Belles Roses but unfortunately she gave no date or other reference for the publication. Everyone loved the rose and eventually it was given a name in 1978 by Ken Knobbs in honor of their beloved Auckland gardener Ann Endt. In a photo taken by K.K. Ziarnek in the Auckland Botanic Garden stipules of ‘Ann Endt’ are barely visible but they appear to be flat! (Now I discover Patricia Routley posted an excellent photo of the leaf with stipule clearly visible on February 13, 2015.) Nancy likely is correct, this maybe was Vilmorin’s hybrid using the true Rosa foliolosa Nuttall ex Torrey & Gray with rugosa as the seed parent but there is some confusion about the flower color, Nancy only saw a black and white illustration.
Therefore ‘Basye’s Purple’ and ‘Ann Endt’ are not the same cross but worthy roses in their own right as is “Hilliers Foliolosa” with its vivid red flowers and most neglected of all but certainly not least, the lowly White Prairie Rose, Rosa foliolosa Nuttall ex Torrey & Gray, 1840!