Final answer:
A leptosporangium is the type of sporangium that produces a small number of spores, as opposed to a eusporangium which produces a larger quantity.
Step-by-step explanation:
The type of sporangium that produces a small number of spores is the leptosporangium. Leptosporangia are found in ferns and some other groups and typically produce fewer spores compared to eusporangia. In contrast, a eusporangium, which is found in other groups including some ferns, horsetails, and marattioid ferns, produces a larger number of spores.