<p>The wheat pericarp plays an important role in endosperm development. A comprehensive understanding of the growth sequence of both the wheat pericarp and endosperm is essential. This study compared the morphological characteristics of pericarp and endosperm in wheat grains of two large-grained varieties (‘Zhongmai578’ and ‘Shannong30’) and a small-grained variety (‘Liangxing68’) at different days after pollination (DAP). On the pollination day, wheat pericarp starch granules, and vascular bundles were well formed in the grains of all three wheat varieties. At 8 DAP, ‘Zhongmai578’ reached maximum mesocarp cell length and pericarp starch granule size, whereas ‘Shannong30’ reached these peaks at a later stage. By 12 DAP, both the maximum particle size of pericarp starch granules and the vascular bundle area had reached their peaks across all three varieties. The relative area of starch granules in the wheat endosperm increased rapidly until 18 DAP, with large-grained varieties having greater starch granule areas than the small-grained variety. In summary, significant variation was observed in the size of pericarp starch granules and the area of vascular bundles in wheat grains. These morphological and anatomical differences are likely responsible for variation in endosperm starch accumulation and increases in grain weight.</p>