Living fossils on campus

Some species have been described over the years as ‘living fossils’ because they are the last survivors from groups that were once common in the fossil record. The Coelacanth is an example. It belongs to a group of fish first known only from the fossil record and very different from all other fish alive today.

The Ginkgo tree (Ginkgo biloba) is another ‘living fossil’. It is the only surviving species from a group of broad-leaved gymnosperms that were widespread in the Mesozoic era 250-200 million years ago. There is a particularly lovely Ginkgo planted behind Whiteknights House on campus.

Ginkgo leaf infected with Bartheletia paradoxa

Ginkgo leaf infected with Bartheletia paradoxa

In autumn the leaves change from green to a pure yellow. They have just finished falling and have become infected with a fungus that is as old and peculiar as the tree!

Bartheletia paradoxa is a basidiomycete that has characteristics unknown in any other basidiomycete living today. The species was first observed in France in 1932 but was not formally described until 2008. Mycologists recorded the fungus on leaves in Kew Gardens the same year. The fungus does not appear to infect the fallen leaves of any other plants.

Large thick-walled teliospores.

Large thick-walled teliospores.

Fallen Ginkgo leaves rapidly become infected by basidiospores released from the remnants of the previous year’s leaves. Growth results in black specks in the center of small brown spots on the leaves and stalks. These black specks are clumps of thick-walled teliospores which will survive on the rotting leaves to release basidiospores the following autumn.

 

This is the first time that Bartheletia paradoxa has been recorded in Berkshire.

 

References:

Scheuer et al (2008) Bartheletia paradoxa is a living fossil on Ginkgo leaf litter with a unique septal structure in the Basidiomycota. Mycological Research 112 1263-1279

About Fay Newbery

PhD student in the Plant Pathology Research Group.
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