http://www.users.globalnet.co.uk/~drc/mnagensiumimages.htm
Here's a link to some pics of M.nagesium in kerala India. For some reason the pics aren't coming up in the middle of the screen, but there are also the same pics on the sunshine seeds website(German web site).
Those plants are really dark, and the leaves look less lance shaped than the ones I have.
After a year and a half mine look exactly the same, as were the seeds, and the thing is they look so distinct compared to other bananas. There might have been a mix up with the seeds/plant ID in India.
Someone else chimed in that there's reminded them of Musa initerans, so maybe there is one that is different than musa cheesmanii, but my M.nagesium 'Florie noir' looks the same(Bought from Ortanque seeds..if I remember correctly)

Here is a link that might be useful: M.nagesium

Where did you get your Musa nagensium?

I have both kinds of bananas. You place them side by side and you can't tell them apart. Some have the red midrib and some don't of both kinds. My largest cheesmani has the red midrib. It has around 4ft of psuedostem. Both of the psuedostems are blue purple. I have musa yunnanasis also and the psuedostems are darker and more purple on the cheesmani and nagensium.

Here's the info on Musa Cheesmani. It says the seeds are slightly flat and rough and warty.

Here is a link that might be useful: Musa cheesmani

Here's nagesuium.
That doesn't exactly clear things up, but it doesn't mention nagesium seed being warty.

Here is a link that might be useful: naga