Anemone

The next white flower on the list of white flowers suitable for the sanctuary decoration is anemone.  One common name for this bloom is "wind flower".  It seems very delicate for use as an altar flower, except in a supporting role to larger sturdier elements. At the same time, the common name "wind flower" evokes the Holy Ghost (see e.g. John 3:8; Acts 2:2.) For that reason, I find it intriguing to think of fitting it into a church flower arrangement for a feast day related to the Holy Ghost, such as Pentecost or Trinity Sunday.

Image: From Wikimedia Commons.  Photograph by Eric Hunt taken in Arkansas of an anemone Virginiana.  Click on this link for Creative Commons file use permission.