Final answer:
Horsetails have a type of sporangium called eusporangium, where spores are produced in a terminal cone-shaped structure at the tip of the sporophyte and dispersed by the wind with the aid of elators.
Step-by-step explanation:
The type of sporangium found in horsetails is the eusporangium. Horsetails, which are vascular plants belonging to a single genus with less than 20 species worldwide, display a distinct growth pattern with photosynthetic stems and small scale-like leaves. Spores are produced in a terminal cone-shaped structure at the tip of the sporophyte, where a cluster of specialized, spore-bearing leaves is located. These spores are then dispersed by the wind, supported by structures known as elators that aid in their release from the sporangium.