Question

Refer to the given figures of Marchantia and identify X and Y.

A. X – Male thallus, Y – Female thallus
B. X – Female thallus, Y – Male thallus
C. X – Oogonium, Y – Antheridium
D. X – Antheridium, Y – Oogonium

Answer 1

Marchantia is a thalloid bryophyte. This means that it is a bryophyte that has a thallus body. Marchantia is a dioecious plant. This means that it has two separate sexes. Moreover, Marchantia belongs to the class of Liverworts or Hepaticopsida.

Complete answer: X – The given image is of a female thallus of the Marchantia. This can be identified by the archegoniophore. The archegoniophore is present on the dorsal side of the thallus. It is a stalked upright receptacle or a special branch. The archegoniophore bears the archegonium.
Y – The given image is of a male thallus of the Marchantia. This can be identified by the antheridiophore. The antheridiophore is present on the dorsal side of the thallus. It is a stalked upright receptacle or a special branch. The antheridiophore bears the antheridium.
Thus, based on the above information we can conclude that X is a female thallus of Marchantia whereas, Y is a male thallus of marchantia.
Hence, the correct answer is option (A).

Note: Marchantia is a thalloid bryophyte. It has a flat body that is dorsoventrally and dichotomously branched. The thalloid bears two to four gemma cups. The gemma cups are stalked, bilobed and multicellular structures. They are shaped like the number eight. The cells are green. Each gemma produces two new plants. The sporophyte completely depends upon the gametophyte. There are rhizoids present on the ventral surface of the thallus. The rhizoids are unicellular.