Coming now to the main question, is 67-305 an amphidiploid or a trispecies hybrid? This is not an easy question to answer, since my garden contained many wild tetraploid roses. One clue can come from growing a population of selfed seedlings, easily done since 67-305 is highly self-fertile. If a third species is involved, then the population should exhibit a noticeable segregation of characters. To my untutored eyes this was not apparent in a small population of 30 selfs which I grew. (I should have grown a larger population and called in a trained taxonomist). Instead, the modest variation which did occur struck me as being that which is normal within many species.
Nevertheless, I must be content with calling 67-306 a probable amphidiploid.
The bush is vigorous, up to six or eight feet, and appears to be intermediate between the ancestral parents. The flowers are single, an attractive bright pink, close to three inches in diameter, and occur in clusters of one to ten. They have little or no fragrance. Blackspot resistance is very good. As might be expected from the parentage, the armature of thorns is downright formidable.