They look like roots but they are characterized by having scale-like leaves and axillary buds at the growth nodes. Bearded iris 'bulbs' are really rhizomes. Tubers are outgrowths from internodes on underground stems. They are characterized by having growth buds of 'eyes'. A white potato is an example of a tuber.
Tuberous roots are actually roots that are specialized to store nutrients.
They grow out of the stem base and they are characterized by having no growth buds or 'eyes'. Dahlia 'bulbs' are really tuberous roots. This sub-section is about the formation, structure and ways to garden with these bulbs and bulb like plants. This sub-section is about the asexual reproduction of plants by the various propagating techniques and the uses of propagation in the home garden. The various ways to propagate by layering, stem cutting or leaf slashing.