The Gametophyte is small, cylindrical & subterranean.

It has an Apical Cell and Dichotomous Branching.

It has  Rhizoids &  can have Gemmae   similar to those on the Sporophyte Rhizome.

It also has Mycorrhizal Fungal associations which are vital for its survival because it is not photosynthetic.

It has Vascular Tissue but this is poorly and unevenly developed.

Due to its small size and the fact that most of its cells are pervaded by fungal hyphae, a Vascular System may be redundant. The Vascular System is, however, a Protostele just like the Rhizome.

Antheridia are Superficial and appear as relatively large globes on the Gametophyte.

Antheridia & Rhizoids on the surface of a Psilotum Gametophyte.

Light Micrograph of Sectioned Antheridia

The Necks of the Archegonia
protrude above the surface of the Gametophyte but the Eggs are embedded in the Gametophyte Tissues.

Psilotum Gametophyte (3 mm long)

Psilotum Gametophyte with Superficial Antheridia.

Dichotomously Branched Psilotum Gametophyte bearing Antheridia, Archegonia and Rhizoids
(Photo by Karen Renzaglia)

SEM of Psilotum Gametophyte showing large Globose Antheridia & Smaller Archegonia (Photo by Karen Renzaglia)

SEM Image of a Psilotum Gametophyte with Prominent Archegonial Necks and Rhizoids
(Photo by Karen Renzaglia)

They are both Subterranean, Cylindrical, have Apical Cells & Branch Dichotomously, have Rhizoids, Mycorrhizal associations &  Protosteles.