Thanks Lari Ann,
A. plumbea is considered a syn. of A. macrorrhizos by both Kew and Tropicos. I don't find reference to 'Nigra' or a subtaxa nigra except on plant sales sites and there are plenty of those. One exception is the USDA plants database and they're usually very slow to update. One common name you find often is Metallic Taro.
Edit:
What I'm getting at is what do we call this distinct, sterile A. macrorrhizos variation (both "A. plumbea" and "A. plumbea nigra") now?
P.S. Your Alocasia 'sarawakensis Dark' (or is it new A. macrorrhizos variant) is amazing.
