Hello!
My wife had a couple dozen peony cultivars in her gardens and kept meticulous records. This one is allegedly "Mrs. A. M. Brand". The description for stems and foliage match, and the specimen is 32" tall. Alas, the flowers have these little red flecks in the center which are typical in "Festiva Maxima", which I also have. It stands well over four feet tall. The blooms are bigger and the foliage isn't as dark or dense. There are very few "Mrs. A. M. Brand" photos to compare to, so I don't know if this may be a color variant or not. The flower sure looks like "Festiva Maxima" though.
TIA for your input.
Mark

Welcome to the site!

Looks like it is Festiva Maxima.

Moving the question to the Peonies forum.

I would guess Festiva Maxima because of its pristine white background adorned with crimson flecks Very pretty and classic

After seeing some extensive lactiflora collections I would be hesitant to assign a NOID plant a cultivar identification unless it is extremely distinct or some records are available that narrow down the field of possibilities. Many look extremely, extremely similar and I imagine even the most experienced peony person with the best of visual memories would have a hard time making a distinction between the huge pool of lactiflora candidates.

My wife kept quite good records of her peonies. Only three cultivars were planted in this particular garden, allegedly: Myrtle Gentry, Sarah Bernhardt, and Mrs. A. M. Brand. The latter is the one in question, purchased in 2005 from New Peony Farm.
Various other gardens contain Chestine Gowdy, Duchesse de Nemours, Festiva Maxima, Friendship, Glowing Candles, Koenigen Wilhelmina, Mrs. Bryce Fontaine, Old-Time Peony (Pink), Old-Time Peony (Red), Queen of Sheba, and Raspberry Sundae, all purchased from commercial sources, and all match the descriptions here. This "Mrs. A.M. Brand" is the only one giving me trouble. :-(
Very best regards,
Mark

There are so many whit doubles that occasionally have red flecks, you have a hard road ahead trying to identify! I'd say right off the bat though that if the foliage doesn't match Festiva Maxima to keep looking, it's not that variety. Every single aspect on a plant will match if they're the same variety with small deviations due to difference in soil makeup. Sports do pop up where part of the plant might display a different aspect, that happens more often on hybrid plants where different peony species or genus are crossed, not as much on what is considered a lactiflora. I'd your wife's plant is in the same soil as the Festiva Maxima your comparing to and the foliage is different then it's not a contender as a match.
I got Mrs A.M. Brand from Countryside in 2018 but it's in a bed that has been overcome with blackberry brambles and probably won't be cleared out for a while yet. Have no idea what has and has not survived in it. LG, did you get that one from Countryside as well? I know our tastes are fairly similar and our orders overlap a lot.

Are there search tools available that let one enter various plant characteristics, such as flower color, type, foliage, etc. that would let me narrow down the possibilities?

Not that I've seen, wish there were. That's actually a good thought for our database here on garden.org or a resource we might be able to pin here on the peony forum. If we can get members who have varieties from a trusted source and our peony community here confirmed it would be a huge asset to take pics of different aspects of the plant and flowers. Since we share root pics every fall we could even have representations of the roots.

Minnesotawildflowers.info has a really nice advanced search tool. You have to plug in the values that you're searching for. Sites like Fieldguide Leps and Fieldguide Birds lets you input a photo, which is then processed by AI to yield ID suggestions. iNaturalist operates in a similar way.
Katy Chayka of Minnesota Wildflowers and Andre Poremski of Fieldguide could be useful resources if you planned to pursue something like this. I can help connect you if you like.
Very best regards,
Mark

I didn't get Mrs A M Brand because she's listed as Late. If you find yours Liz, it will be interesting to see if it opens for you.

Remember at the Convention last year in Michigan we both noticed how many different varieties there were of white doubles with red flecks in their historical collection!? It is so very hard to make a true ID on those.

Absolutely, LG! I kick myself now for not taking pics of each flower and ID. Although seeing several there with wrong tags didn't make me feel confident in their ID skills.