The birds, the bees and the Cretaceous plants

cluster of 18 tiny flowers was found preserved in amber in Burma. This very well preserved budding plant shows the oldest direct evidence of sexual reproduction in flowering plants. Scientist from Oregon State University, collaberating with researchers in Germany, published their findings in the Journal of the Botanical Institute of Texas.

The plant has been named Micropetasos burmensis and each flower is only a couple of millimeters long. Preserved in the mid-Cretaceous period, these flowers give a sense of how the environment of the Earth begun to change with the emergence of flowering plant life. Whilst dinosaurs where still very much the dominant form of life, new lineages of mammal and birds where gradually emerging and the Earth began to change.

At that time much of the plant life was composed of conifers, ferns and mosses - a rare few of these species survive to this day. The evolution of flowering plants promoted a huge change in the biodiversity of the planet, especially around the tropic. Although the plant species found preserved in amber is now completely extinct, this is the most complete specimen of any flowering plant from that era of our planet's history.

100-million year old flowers. Image credit: Oregon State University ©Oregon State University; Image credit: Oregon State University

The most remarkable thing about this find, however, are the pollen tubes growing out of two grains of pollen. These penetrate the flower’s stigma (for those whose GCSE biology is rusty, that is the receptive part of a plant's female reproductive system) which would then go on to develop seeds. The rapidness of amber preservation allows this action to be seen now, frozen in time, in "mid-act" as it were.

The pollen is said to appear "sticky", possibly it was carried by insects from flower to flower. Many flowering plants today rely on insect pollination, hence why the declining bee population is so worrying. It is these mechanics of flowering plant reproduction that are still in play 100-million years later.

Unfortunately for the keen Jurassic Park fans out there, it is not possible to grow the seeds preserved in the lump of amber. DNA has a half life of about 500 years (half of it will have degraded after that time) and after 100-million years there is nothing left to sample.

The Yorker, 5/1/14