This is a very handsome free blown American glass Cloche. A cloche is a bell shaped glass cover which is placed over a plant to protect it from frost and to force its growth. Very few of them have survived, primarily because they were used outside in the garden and usually were broken from use or hail.
This one has very fine form, the pictures do not do it justice. It is free blown, there are bubble and lines in the glass. The ring was made seperately and applied to the body. The rim is folded to the inside.
There are no chips, cracks or any other damage, it is in pristine condition. It is 10" tall and ~10-1/4" in diameter.