If you can, find a book called The Biology And Evolution of Fossil
Plants by Taylor and Taylor. It and a basic plant physiology text may
well answer many of your questions. Even many early/lower plants
were/are more complex than "throw it in the air." For example,
bryophytes show alternation of generations--the spores may well be
wind-dispersed, but the sperm of the sexual generation needs water to
swim to the egg. Colonization of drier environments did require
larger propagules with a reserve of food and moisture--seeds. That's
where "seed ferns", gymnosperms, and flowering plants come in. The
Taylor text discusses all sorts of entities with no modern analogs, so
you may find something less "boring" than modern plants.

M. Reed

Gabriel wrote:

I am looking for information on evolution of sporing plants (ferns,
mosses, mushrooms) on land. We have both fossils and living
representatives of flowering plants having different means of
propagating their seeds and increase success rate of their seeds. The
surviving sporing plants that we know seem to have a monotonous
history, that means Throw spores in the air and let chance do it's
task but was it always like that ? For example, were spores always
very small, or were some of them bigger and had a greater reserve of
food and water for dry climate ? Do we have fossilized records of
spores being swallowed by grazing animals and made benefit from the
animal manure for a better success in germinating ? (Just like many
plants which make an edible fruit for propagating seeds that way,
although fruits in sporing plants might be absent.)