primitive plant spores that first appear in the fossil
record during the late Ordovician
to early Silurian
Evidence that cryptospores derive from land plants
Cryptospores are generally found in non-marine rocks
and decrease in abundance with distance offshore. This suggests that any cryptospores found in the marine
environment were transported there by the wind from the land, rather than originating from the marine environment.
walls of cryptospores consist of many lamellae (thin sheets). Liverworts
, thought to be the most primitive land plants, also have this spore wall morphology
Recently, fossils of plant sporangia
have been found in Oman
with cryptospores showing concentric lamellae in their walls, similar to liverworts.
Steemans, P. (2000). "Miospore evolution from the Ordovician to the Silurian". Review of Palaeobotany and Palynology
113 (1-3): 189–196.