Geastrum pectinatum has been mistaken for the morphologically similar but smaller species G. schmidelii.
The latter species lacks vertical striations on the basal portions of the endoperidium, and does not have a pseudoparenchymatous collar around the stem.
Another similar species, G. berkeleyi, has a shorter stem and is missing the ridges at the base of the spore sac.
Further, the color of its spore sac is usually brown, in contrast to the gray-blue of G. pectinatum.
G. xerophilum also has a dusting of white powder on the surface of the spore sac, but unlike G. pectinatum, consistently lacks a ring at the base of the pedicel; furthermore, in contrast to G. pectinatum, the spores of G. xerophilum are yellow and contain oil drops that are readily observable with a microscope.
G. striatum has smaller fruit bodies than G. pectinatum, and a distinct collar-like apophysis.
Geastrum pectinatum has been mistaken for the morphologically similar but smaller species G. schmidelii. The latter species lacks vertical striations on the basal portions of the endoperidium, and does not have a pseudoparenchymatous collar around the stem. Another similar species, G. berkeleyi, has a shorter stem and is missing the ridges at the base of the spore sac. Further, the color of its spore sac is usually brown, in contrast to the gray-blue of G. pectinatum. G. xerophilum also has a dusting of white powder on the surface of the spore sac, but unlike G. pectinatum, consistently lacks a ring at the base of the pedicel; furthermore, in contrast to G. pectinatum, the spores of G. xerophilum are yellow and contain oil drops that are readily observable with a microscope. G. striatum has smaller fruit bodies than G. pectinatum, and a distinct collar-like apophysis.
Geastrum pectinatum