A spore is a microscopic grain, made in enormous numbers, from which a new plant can grow. Unlike a seed (Definition 9.1), a spore is a single speck with no food store and no ready-made tiny plant inside — it is a beginning at its barest.
Examples
Example 24.2 (Under the fern’s fronds)
Turn a fern frond over in late summer: neat rows of brown dots line its underside. Each dot is a packet of thousands of spores; ripe, the packets split, and the spores drift off on the air like the finest dust. A spore landing on damp shaded ground can grow — by stages — into a new fern.