a type of yam old-Boie’nen people turn to during rice-shortage season in the olden days. Its tuber is toxic when fresh due to the presence of saponins and calcium oxalate raphides, so it must be processed prior to consumption, typically by finely slicing into thin chips, placing in a sack or net, and leaving in a stream for a few days until the toxins have leached out. It is then dehydrated and cooked.