maggot stone from Kleinnaundorf near Freital, detail
Cross section of fertile pinnules of the tree fern Scolecopteris/Psaronius,
looking like seagulls in flight. Clusters of sporangia, called synangia, are
seen
attached to the lower side and virtually enclosed by the pinnules. Obviously,
synangia make up a large part of the plant remains. Pinnule width up to 2 mm.