Chinese yam (Dioscorea polystachya) growing along the banks of Knoxville's Ten Mile Creek, on the greenway.
The 10 mm "bulbils" break off, float away, and form new plants. Chinese yam is an old Chinese garden escape that is becoming a serious invasive, sometimes worse than kudzu, in the southeastern USA - it is spreading very rapidly along Knoxville's creeks. The large underground tuber is widely eaten in China, Japan, and Korea - I haven't tried it. See the Wikipedia article about the Chinese yam.