Fragments of the earliest land plants

Twelve spore-mass fragments from Ghaba-1 core 21 in northern Oman came from deposits assigned by the source to the Late Ordovician Caradoc using palynology and sequence stratigraphy; the atlas uses a broad Sandbian–Katian display window rather than pretending the legacy stage assignment is an exact numerical date.

The Oman fragments preserve masses of naked or envelope-enclosed permanent tetrads or naked dyads, with some presumed sporangial covering; this directly supports land-plant spore production, while lamellate wall ultrastructure only suggests, and does not establish, liverwort affinity.