These are OP hips, and are a truly rare finding/phenomenon in my climate.
The surrounding roses which might have contributed the pollen include:
Elina, Pat Austin, unidentified DA pink, Queen Elizabeth, Scarlet Queen Elizabeth, Mount Shasta, Eiffel Tower, unidentified yellow/pink bicolor HT,
and some presumed non-tetraploids (which I highly doubt would be dad): Iceberg , Lamarque, Seafoam.
The bush is grafted on multiflora, and has never been pruned and stands real tall, much taller than me, and the hips were right at the very tops of the plant.
Sydney weather this summer just past had been almost record rains, and had been unusually cool. Maybe those conditions were favorable to the hip set, but that is counterintuitative to what I would have thought, so…I know, it is anyone’s guess!!
I kinda doubt any of these will germinate, but I’ll try (zip-lock baggy, wet paper toweling and fridge, after first giving them a period of warm stratification in the baggy/wet paper).
The same bush gave one OP hip last year with I think one lone seed in it, but if my memory serves me right I tossed it all out as it was picked very green and opened on a whim just to see if the hip contained seed.
That is what spurred me on to check the bush out real carefully this season. The hips were still green but just starting to turn a lighter color, so I think they are mature enough.
There are two Elina bushes in the garden, both budded on multiflora, and both are the same age: One gets pruned lightly every winter, and the one which has set these OP hips is unpruned (as mentioned earlier). The one that gets the pruning has never set OP hips to my knowledge.