Let’s look more closely at the flower from the side . . .
By mid-summer, the leaves have filled out and exhibit their alternating pattern along the stem. You can see how similar this plant looks at this time to both Solomon’s seal (Polygonatum biflorum) and False Solomon’s seal (Smilacina racemosa).
Note the supporting structure for Mountain bellwort. It has a single stem which forks into two stems with alternating leaves. This is in contrast to Solomon’s seal (and False Solomon’s seal) which have a single stem of alternating leaves.
Let’s look more closely at the developing seed capsule.
Here’s a view of Mountain bellwort in the late summer / early fall when the leaf color begins to change from green to yellow.
NOTE (11/25/13): When I first discovered this plant in 2009, I thought it was Sessile bellwort (Uvularia sessilifolia). I created this blog post in 2011 — describing what I then thought was Sessile bellwort. Recently I re-read the plant’s description in several field guides and realized I had made an error. This is Mountain bellwort (U. puberula) because it has fine (downy) hairs along the upper stems and at each leaf node. The primary vein on the underside of the leaf also has fine hairs. In contrast, Sessile bellwort has smooth, hairless stems and leaves. In all other significant characteristics, the two plants look the same. For some good photos of U. sessilifolia, visit the GoBotany site for New England wildflowers.
You might also enjoy watching an in-depth video plant portrait for Mountain bellwort.