Recently, I collected fossils from the famous posidonia shells from the lower Jurasic (Toarcium or Lias epsilon) in Holzmaden in the south west of Germany near Stuttgart. Besides numerous Ammonites I found some of the following fossils which I don't quite know what it is. Any ideas? They are quite thick "leaves" which seem to be connected to some thicker more or less spherical stem(now completely pyritized in the upper part of the picture) altough I did not prepare them, so the anatomy is just a guess. The size is about 3 cm. Thank you!