Final answer:
The Whisk Fern (Tmesipteris) bears a type of sporangium known as eusporangium, which is larger than leptosporangium and develops on yellow knobs at branch tips or nodes.
Step-by-step explanation:
The type of sporangium found in the Whisk Fern (Tmesipteris) is an eusporangium. Unlike leptosporangia, which are found in most other ferns and are typically small stalked structures with a band of specialized cells called an annulus, eusporangia develop from a group of epidermal cells and are comparatively larger. In whisk ferns, sporangia develop on small yellow knobs at the tip of a branch or at branch nodes. These yellowish sporangia are conspicuous and spherical, which are characteristic features of whisk ferns such as Psilotum nudum, a species within the class Psilotopsida.