Hello gardeners

I am trying to solve this mystery plant. Could anyone verify if it is a fern at the very least?

The photo was taken at the UC Berkeley Botanical Garden in California. Since it was in botanical garden the species could be a non native plant. I have contacted the garden's horticulturalist but he is on vacation and this is in sort of a time crunch.

From my memory the spread was quite big maybe a few feet, 2 or 3 feet, in width and the plant was as high as 3 feet? The width may be smaller but I do for sure remembering having to be on my tip toes to take this photo because i wanted this angle and I am 5 2" so it had to be somewhat tall. For sure though, this photo was taken in July.

Thanks for any help and I appreciate your time.

Hello and welcome catherine.

Where are your location ? You can complete your profile that will help other to give the right sugestion.

Fern are a bit hard to identify since it have similar appearance. My wild guess it is a kind of Athyrium. Some of them have red tinge stem and leaves