A number of potentially poisonous, white mushrooms are similar in appearance when they are in their immature button stage and lack a visible stem. Button-stage mushrooms differ in that they exhibit the faint outline of gills or other structures when cut in half, rather than having undifferentiated flesh. The poisonous earth balls
(species of Scleroderma
) are superficially similar, but are tan or yellowish to brown rather than white, lack spines, and have a black interior (though when very young, the interior is whitish). The not-recommended Lycoperdon marginatum
differs in that the spines group together and join at the tips and do not shed individually but rather peel away in patches or sheets. The probably edible Vascellum curtisii
differs in that it is smaller (under 2 cm broad) and has longer spines (up to 5 mm long) that join together at the tips to form spikes, though the spines often fall away. Species of white puffball that lack spines at any stage, including Calvatia cyathiformis
and Bovista plumbea
, are generally edible if the interior is all-white.