Just to clarify and add to what Ty has posted, all banana plants have a corm no matter how they were produced (from tissue culture, a sucker/pup, or even seed). The corm of a banana plant is the true stem and it is where all new roots, shoots and leaves grow from. It is a solid, starchy tuberous-like organ which really in a sense the true core of the plant, and if you were to receive a new sucker that is without a corm (as can easily happen when separating suckers without much experience) the plant will not grow. It is normally mostly underground. What appears to be the above ground stem is called the "pseudostem", and it is kind of like a giant leek, and is composed only of leaf tissue until the plant flowers at which point the corm will send up a true stem through the center of the pseudostem and out of the top to expose the flowers.
