Could be Ms Bateman or Henrii. I say Ms. Bateman. I have both!

sandyl, I have both Ms Bateman and Henrii in my yard, neither of them looks like this.

This clematis has a round tip of the petal.

Is 'Henryii' too pointed?

"Candida' seems to cary 8-9 sepals and 'Guernsey Cream' seems to have sepals that show their narrowness at the center. 'Huldine''s sepals don't overlap the same way in the pics I saw.

'Lanuginosa Candida' or 'Tsuzuki' at clematisqueen are both all white.

'Marie Boisselot' and 'The Bride' are two more. Let us know if you id it. Nice picture.

Hello, Iris,
After checking one by one the names you provided, I think it should be 'Lanuginosa Candida'. Thanks very much.