sentences:  One theory, the "enation theory", holds that the microphyllous leaves of clubmosses developed by outgrowths of the protostele connecting with existing enations The leaves of the Rhynie genus "Asteroxylon", which was preserved in the Rhynie chert almost 20 Million years later than "Baragwanathia" had a primitive vascular supply – in the form of leaf traces departing from the central protostele towards each individual "leaf".