 Young specimens of A. hygrometricus have roughly spherical fruit bodies that typically start their development partially embedded in the substrate . A smooth whitish mycelial layer covers the fruit body , and may be partially encrusted with debris . As the fruit body matures , the mycelial layer tears away , and the outer tissue layer , the exoperidium , breaks open in a star @-@ shaped ( <unk> ) pattern to form 4 – 20 irregular " rays " . This simultaneously pushes the fruit body above ground to reveal a round spore case enclosed in a thin <unk> <unk> . The rays open and close in response to levels of moisture in the environment , opening up in high humidity , and closing when the air is dry . This is possible because the exoperidium is made of several different layers of tissue ; the innermost , fibrous layer is hygroscopic , and <unk> or <unk> the entire ray as it loses or gains moisture from its surroundings . This adaptation enables the fruit body to disperse spores at times of <unk> moisture , and reduce evaporation during dry periods . Further , dry fruit bodies with the rays curled up may be readily blown about by the wind , allowing them to scatter spores from the pore as they roll . 
