mardi 26 avril 2016

Accueil > Les rubriques > Société > The Dawn of Flowers

The Dawn of Flowers

2e partie

, Alain Wagner , Mark Brown , Martial Verdier et Virginie Rochetti

Toutes les versions de cet article : [English] [français]

In 1998, the Annals of the Missouri Botanical Garden published an article that revolutionized the world of plants and their taxonomy. Until that time, scientists had been decoding the genetic sequences of various simple organisms, but botanists could only classify plants according to what we all can see, augmented by chemical analysis.

A Park of Bygone Landscapes.

Reportage video de A. Wagner dans le jardin botanique de Marc Brown en Normandie le 29/08/2015 de 14:27 à 16:47.
La forêt sera magnifique, il faudra y revenir un jour…

Now, with the increased capacity of computer power and memory, it has become possible to take on whole sections of plants or animals and decode and unwind the relationship of one species, genus or family to another. Appearances, we have learned, are not always what they seem : Various characteristics that once were deemed salient, now are shown to be the result of adaptation (parallel evolution), or simply fortuitous. Now complete studies have been made of genetic groups and a fascinating spectacle has been revealed to everyone.

Thanks to this generous and truly revolutionary study by the Angiosperm Phylogeny Group (A.P.G.I, we are now in the third version A.PG.III), we are much nearer to resolving what Darwin described as an "abominable riddle” ; that is, the origin of flowering plants (angiosperms). How he would have been fascinated ! Angiosperms are now much better understood than ever before. The angiosperm fossil record is patchy and incomplete when compared to that for the gymnosperms, i.e. conifers, ginkgoes, cycads etc., which have a fairly clear record. Yet, due to this work, we now a have a chance to see what the first landscapes with flowering plants looked like. We can follow evolution from the first cretaceous forests where Metasequoia, Ginkgo, Araucaria and other conifers thrived, and we can understand how these early forms fitted into these landscapes by studying their present day biotopes.

My work of over thirty years of creating landscapes small and large with an increasingly strong bias towards wild-land communities of native plants has lead me to reflect on these contemporary biotopes. Naturally, my experience led me to wonder why all these primitive plants couldn’t be brought back together as evidenced by the fossil record and the interpretation of the results of genetic analysis. This speculation quickly grew into a desire to recreate these bygone scenes. So it became necessary to find a suitable place to do so, and in the process, establish a living research center ; the Normandy coast proved to be the ideal location as it is blessed with several factors :
1. An equitable, moist climate.
2. Many renowned gardens and gardeners are established in the region, a testament to the suitability of the site and a fact that also provides a ready public audience who would visit and sustain the project.
3. Paris and London are not that far off : Paris is roughly two hours drive away. The cross-channel ferry serves Dieppe several times a day providing a practically direct link with London, via Newhaven. This means that botanists wishing to examine and compare the morphology of this group of plants can do so relatively easily. Accommodation for researchers is planned.

Since February 2004, along with well over a hundred trees and lesser plants sited in one section, I have systematically, and at my own expense, thus far planted 2.2 hectares (approximately 5 acres) of land along the coast on a south-facing slope that runs down from the clay plateau of the Ailly. This site is regularly flooded, and so communities of giant horsetail (Equisetum telmataiea), bracken (Pteridium aquilinum), adders tongue (Ophioglossum vulgare), Osmunda regalis and Scots pine flourish.
Many botanists believe that angiosperms evolved from aquatic or waterside plants ; water lilies (Nymphaea) are the most primitive of hardy flowering plants, only one small evergreen understory shrub from the rain forests of the highlands of New Caledonia is more primitive. And the earliest known angiosperm fossil (found in fine sediment rocks in southern China), Archaeofructus, was an aquatic plant that held its flowering spike above water. Many other primitive plants besides these angiosperms are moisture-loving, tree ferns, Equisetum, Osmunda and Taxodium for example. The first monocotyledons (an early branching of angiosperms) are all waterside or aquatic plants. The hornworts (Ceratophyllum) sister group to these plants are totally aquatic. Many magnolias are swamp plants. Saururaceae (lizard tail and yerba buena etc.) are all wetland and semi aquatic plants. As already mentioned Nymphaea and its relatives Nuphar and Brasenia, and its sister family, Cabombaceae, which is sometimes included in the Nymphaeaceae, are all aquatic, bar one obscure tropical species.

Therefore, a series of wetlands and pools is a vital part of the project. One large pond that no longer holds much water is still in place, but that is all. I have determined that five ponds are necessary, these to rhythm and punctuate the project, and which will recount the different stages of angiosperm evolution as revealed by genetics. Water is abundant above the site on the clay plateau and drains down the slope, so filling the ponds will not be a problem. Clay is present at various depths to make the ponds watertight. However, machinery and manpower are needed to realize this aspect of the plan. Any organizations that are interested in helping financially or otherwise with this part of the project are welcome.

It’s time that botanists and lay people alike have a chance to see, touch, taste and listen to these plants in situ. Too often, genetic researchers don’t know what the plants they are studying actually look like, as helpful as it might be to know ! Yet they haven’t the time to go around all the gardens or wild places where these plants can be found.
So, is it not reasonable, even imperative that research botanists and the public have an opportunity to see all the plants growing together in one dedicated site in this mild corner of Normandy ? The recreation would offer visitors the chance to experience and understand the long-vanished biotopes of pre-Ice Age Europe, and provide a unique opportunity to understand the evolutionary process.
Plants are the basis for all life. Understanding plants is to understand insects, reptiles, mammals and therefore us. I hope that this project will fire the imagination of others and stimulate a new perspective and fresh understanding of the plant kingdom and open the door to new discoveries. Already at this early stage certain new ideas are raising their heads.

I hope that other people, botanists or enthusiasts, will join me on this voyage of discovery. Anyone that has a love of nature, plants and especially evolution, and who has an inquiring mind is more than welcome to participate, at any level, in the creation of the project. It is early days yet, but I am more than happy with the response so far generated. Already botanists are curious about the project and are asking for material from the plants to study. I ardently hope that this is just the beginning of a shared vision, for the future of the project goes well beyond me. The trees will grow and mature well beyond my lifetime, so this place is a gift to future generations.

Sur le travail et un texte de Mark Brown, une interview de Virginie Rochetti réalisée et montée par Alain Wagner. 2e partie