I have had a private query on the parentage of ‘J. Otto Thilow’. In the hope that more information may come to light, I am replying publicly:

The rule is the seed parent always comes first.
From 1930 Modern Roses 1, page 1:
"Where two parents are shown, the first is usually the seed-bearer".

I have a funny feeling that there was one small country who earlier listed the pollen parent first, but without spending time researching this, I cannot remember which country. Could it have been Holland in the early days? If so, it could explain why Hazlewood in 1928 listed (Souvenir de H. A. Verschuren x Hadley). He explains in his 1928 reference that the main description came from the breeder, and until he knew the rose better, he was adding his own brief comments in italics. I have added a Note to this reference.

A question remains for me - did he get his budwood from each breeder? (There were so many); or did he get his budwood from an agent, or big nursery? Someone told him the parentage he listed.

Most later references show J. Otto Thilow's parentage as (Hadley x Souvenir de H. A. Verschuren) and HMF initially showed this parentage as listed in Modern Roses 1. When I later started adding references the reversed parentage in Hazlewood's catalogues came to light. We have added a Note that there is a discrepancy.

Frank Reader’s parentage suggests that the breeder was popping the pollen of Souvenir de H. A. Verschuren on to more than just J. Otto Thilow.
1927. J. Otto Thilow (Hadley x Souvenir de H. A. Verschuren)
1927 Frank Reader (Golden Ophelia x Souvenir de H. A. Verschuren)