How do microspores and megaspores differ in heterosporous plants?

In heterosporous lower vascular plants, such as certain lycophytes and water ferns, the plant produces two distinct types of spores that differ in size, function, and the resulting gametophyte they produce.1

• Megaspores: These are relatively large spores produced in specialized structures called megasporangia. They contain food reserves essential for the early development of the embryo and germinate to form a female gametophyte, which produces archegonia and eggs.21
• Microspores: These are produced in large numbers within microsporangia. They are significantly smaller than megaspores and germinate to form a reduced male gametophyte, which consists of little more than a jacket of cells and the sperm cells.21

This heterosporous condition contrasts with the more common homosporous state in lower vascular plants, where all spores are morphologically identical and typically produce bisexual gametophytes.13