Yellow Mandarin, Fairy Bells
Disporum Lanuginosum

• Flower: Green, consisting of 6 long pointed perianths, single or in an umbel of a few. 1/2"-1" across
• Leaves: Oval to lance shaped, stemless or clasping (but not perorated by the stem). Alternate, exept the last ones may appear opposite
• Height: 12"-36"
• Habitat: Rich woods.
• Blooms: April-May

I've only seen this one once—the delicate green flowers would be easy to overlook.