Final answer:
Blue granules indicative of starch would be found in the cortex parenchyma cells of the root after staining with iodine, as these cells are where plants typically store starch.
Step-by-step explanation:
When a section of buttercup root is stained with iodine to detect starch, one would expect to find blue granules indicative of starch in the cortex parenchyma cells of the root. The iodine test is used to identify the presence of starch because iodine reacts with amylose, a component of starch, to form a blue-violet complex. This test is sensitive enough to detect even small amounts of starch. Therefore, the expectant blue granules, representing starch accumulation, would typically be found in the cell cytoplasm within the cortex, which is known to be an area where plants store their starch reserves.