The tuberous spiderworts are a group of plants in the genus Commelina, better known as ornamentals called dayflowers.  Taxonomy is a little uncertain with this group.  Depending on which references you use, the tuberous spiderworts may comprise four species (C. coelestis, C. dianthifolia, C. elliptica, and C. tuberosa) termed the C. tuberosa complex.  Or, they may all be synonymous with C. tuberosa.  The species that are most widely available are C. coelestis and C. tuberosa.  As you might expect from the taxonomic confusion, they are all very similar and they appear to interbreed readily.

All parts of the plant are edible, except perhaps the flowers.  They might be, but I’m not sure.  Leaves, stems, and tubers are edible.  The tubers form a small clump of fingerlike tubers, about the size of a child’s little finger.  That’s really not bad for an ornamental edible and it is likely that yield can be improved with selection.  The flavor is nothing to write home about.  In fact, it is almost totally neutral, taking on the flavor of whatever it is cooked with.  Texture is something like a slightly sticky potato.  In all, I find it totally inoffensive and compatible with a lot of dishes due to its unremarkable profile.

The plant seeds heavily, which may be good or bad, depending on your goals.  In the right climate, it can be pretty invasive.  I find that mulching around the plants helps to cut down on volunteers.  Reproductive pruning – cutting off the flowers before they can form pods – also cuts back on self-sowing and seems to improve the tuber yield.