The fruit of Ipomoea batatas is a dry capsule. Ipomoea littoralis is another species with dry, buoyant capsules that facilitated its wind and water borne distribution to Polynesia through to Madagascar beginning 1.1 million years ago. https://t.co/mPEpRGnpjh
The authors established a molecular clock for Convulvulaceae which estimates the Polynesian sweet potato as having diverged from American populations >100,000 years ago. Long distance natural dispersal in Ipomoea occurred in at least two species, I. littoralis and I. tuboides.
