The outermost and innermost wall layers of microsporangium in an anther are respectively.

1. Endothecium and tapetum

2. Epidermis and endodermis

3. Epidermis and middle layer

4. Epidermis and tapetum

A typical microsporangium is generally surrounded by four-wall layers, /.e., the epidermis, (outermost protective layer), endothecium, (middle fibrous layers), and the tapetum (innermost nutritive layer).
Page 21, XII NCERT