Geastrum saccatum Nested Earthstar
The outer wall of this earthstar splits and reflexes to form a bowl in which the spore sac "nests" (= saccate). The fruitbodies in the Nested Earthstar are only a centimetre or two across. This close up was actually taken in the lab sitting on a sheet of glass with a few pine needles from the locus natalis scattered around. In its nesting habit, this species resembles G. fimbriatum but the latter has a poorly defined mouth. In G. saccatum the mouth (= peristome) is clearly demarcated from the rest of the spore sac. Geastrum triplex is also saccate but is much larger (up to 10 cm across).