This document from Universitšt Hohenheim in Germany mentions that Nelumbo nucifera Gaertn. rhizome is [...] "rich in Vitamin B12, rare among vegetables". Many of the 50-100 references we have listed mention that B12 is rare in plants - several of them claim that the plant they mention more or less is the only one that contains B12. They should visit this subforum more often.

(Source: Development and Evaluation of a System for the Study of Mineral Nutrition of Sacred Lotus (Nelumbo nucifera) by J.H. David. Doctor Thesis. University of Western Sydney, Hawkesbury, Australia)

I'm always a little skeptical when someone mentions nutrient levels (B12 in particular) without references to the actual studies they have this information from. I still post links to these articles here - maybe these threads can serve as background material for researchers who have the budgets and labs it takes to find the detailed B12 level for specific plants, incluidng the active/inactive analogue ratio? Hopefully they'll perform the tests on fresh, organic plants, so the results aren't distorted by the expected B12 decrease derived from non-organic farming, exposure to light, ageing, exposure (before B12 is measured) to chlorinated water, heat and so forth.