Alexis continues with the prehistoric plant series she assembled in the summer:
Plants of the Psilotales, such as the pictured Psilotum nudum, are recognized as the most primitive plants currently living. Psilotum species are known as whisk ferns and though they do not appear in the fossil record, they share characteristics with extinct flora like Cooksonia.
The Rhynie Chert in Scotland is a sedimentary rock formation that contains a variety of fossilized plants and animals from the Early Devonian period, about 400-412 million years ago. It contains very well-preserved specimens of early vascular plants like Aglaophyton, which, like today’s Psilotum, had no true leaves or roots, possessed rhizomes and sporangia, and a dichotomous branching pattern. Additionally, there is evidence that Aglaophyton species were myco-heterotrophic, having a symbiotic relationship with arbuscular mycorrhizal fungi that helped the plant to absorb nutrients; fungi often associate with present-day members of the Psilotales in the same way. Because of their similarities to Devonian flora, whisk ferns are uniquely significant for research purposes.