"Inspect the circle" with nothing planted and Ocean Sight active:
(basic shrooms: edible mushroom, large mushroom, red toadstool, warty toadstool)
1st time: 5 basic shrooms
2nd & 3rd: 3 basic, 1 destroying angel
4th: 3 basic, 1 black spores
5th: 3 basic, 1 destroying angel
6th: 4 basic, 1 angel
7th & 8th: 3 basic, 1 angel
9th: 4 basic
10: 4 basic, 1 black spores
11th: 3 basic, 1 angel
12: 4 basic
13: 3 basic, 1 angel
14: 4 basic, 1 black spores
15 & 16th: 3 basic, 1 black spores
17th: 4 basic, 1 angel
It looks like it's pretty much just chance, probably with a unique result the first time per day (5 basic mushrooms). Ah well.
In the beginning, men were mortal.