Final answer:
A male gametophyte of Marchantia viewed under a microscope will reveal antheridiophores which are stalked structures bearing the sperm-producing antheridia. The gametophyte shows a complex thalloid structure with distinct cell layers, and asexual reproduction can also be seen through structures called 'splash cups'.
Step-by-step explanation:
Under a microscope, a male gametophyte of Marchantia displays distinct structures known as antheridiophores. These umbrella-shaped bodies rise above the main thallus and are the site for antheridia production, which eventually produce sperm. The antheridiophores are recognized by their stalk that elevates the antheridia-bearing platform from the surface of the thallus. This male gametophyte structure is essential for sexual reproduction in Marchantia, enabling sperm production and release.
Marchantia shows alternation of generations with a dominant gametophyte stage. The male gametophyte, which is larger and more persistent, can be observed under the microscope as having a complex thalloid structure with multiple cell layers, open pores for gas exchange, and a bottom layer helping in anchorage through rhizoids. The gametophyte's ability to reproduce asexually can also be noted through visualization of 'splash cups' containing gemmae, another key feature under microscopic observation.