Hi Mal,
Glad you had a good time.
At the base of the spore sac, there is a very distinct collar where it is attached to the stem, (no hand lens needed).
Be careful though when looking as the collar in young fruitbodies can sometimes hide the stem giving the impression there is no stalk.
This is where I am going to give a free plug for the new Collins book, because
it covers the Earthstars extremely well with some excellent photos.
Just go to page 273 and you will see
G.striatum & G.pectinatum side by side for a clear comparison.
There is even an extra photo below of
G.pectinatum with a slight variation where there is a 'chamfered' connection of the spore sac to stem, but the collar on
G.striatum is always distinct giving the impression it is
free of the stem
Hope that helps.
Neil.
Afterthought: Just think of the sliding ring on a
Macrolepiota procera stem, now imagine the top of the free ring connected to the bottom of the spore sac of
G.striatum where it meets the stalk. This is not a perfect description of what the collar looks like, but it's the best I can come up with.