Roth IRA

Dear Liz: I inherited my mother’s Roth IRA when she died in 2015 and have been taking yearly required minimum distributions based on my age.

Can she just roll it over into her existing Roth IRA, as is generally permitted for spousal IRA inheritance?

My spouse is my primary beneficiary on this inherited Roth IRA.

Or are there additional limits imposed because it becomes a “doubly inherited” Roth IRA?

Since this is a Roth IRA, however, the original owner would not have been required to start distributions.