Gametophytes of Marchantia
Top Canon 10D with Kiron 28-85mm Macro
Lower two Canon Pro 90IS with E3500 close up lens
I present three photo macrographs of the common leafy Liverwort Marchantia. The upper image shows a fresh spring growth amongst moss. The middle image a leaf, out of which gemma cups containing gemmae have grown up, plus a mature Archegoniophore (flower petal like feature –upper left) of the female gametophyte. I came across this specimen too late in the season to catch the Antheraidiophore of the male gametophyte which is necessary for sporophytic generation of the liverwort.
The lower image shows a close-up of the gemma cups and the gemmae they contain. They can be seen as the green disks in side the cups. The liverwort uses these to reproduce asexually when washed out by raindrops. Please see my post on the photomicrography forum for close-ups of the gemmae.
Walt
I find liverworts quite common around areas of freshwater run off here in the mountains, some are associated with mosses, others are not. Personally I have never observed the gemma of any liverworts, I suppose I have not been in the right places at the right time, but I have read a little on the reproductive cycle of these plants. 
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