In the dasheen types of taro, the corm is cylindrical and large. It is up to 30cm long and 15cm in diameter, and constitutes the main edible part of the plant. In eddoe types, the corm is small, globoid, and surrounded by several cormels (stem tubers) and daughter corms. The cormels and the daughter corms together constitute a significant proportion of the edible harvest in eddoe taro. Daughter corms usually give rise to subsidiary shoots even while the main plant is still growing, but cormels tend to remain dormant and will only give rise to new shoots if left in the ground after the death of the main plant. Each cormel or each daughter corm has a terminal bud at its tip, and axillary buds in the axils of the numerous scale leaves all over its body.

That’s from an FAO publication. I’m pretty sure most South Pacific material is the dasheen type, but the photos of the South African corm look more like eddoes. I think the eddoe is generally considered closer to the wild type, which has small corms and runners, but I could be wrong.