Gold Coast Cymbidium Growers

This was because the plants, which bloom only infrequently, grew in tropical areas where the hot, humid conditions prevented fossilisation, he said.

 A lack of evidence from the past meant the evolutionary history of the plants was shrouded in mystery.

While some scientists believed orchids must have arisen relatively recently because of their need for such a variety of insects to pollinate them, others argued they must be older because of their huge diversity.

Dr Ramirez's team identified the family of orchid the pollen came from, based on its shape, and then used genetic comparisons of existing orchids to estimate when the first orchids appeared.

"Our analysis places orchids far towards the older end of the range that had been postulated," Dr Ramirez said. The study, published today in the journal Nature, concludes that orchids first evolved between 76 million and 84 million years ago, when Tyrannosaurus rex still roamed the Earth.

The orchids flourished, branching into their many different forms soon after the disaster 65 million years ago that wiped out the dinosaurs.

 ( See actual scientific abstract below).

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From an abstract of the Journal Nature 448, 1042-1045 (30 August 2007) | doi:10.1038/nature06039; Received 17 January 2007; Accepted 21 June 2007

Dating the origin of the Orchidaceae from a fossil orchid with its pollinator

By Santiago R. Ramírez of Harvard University, Barbara Gravendeel, Rodrigo B. Singer, Charles R. Marshall & Naomi E. Pierce

Since the time of Darwin, evolutionary biologists have been fascinated by the spectacular adaptations to insect pollination exhibited by orchids. However, despite being the most diverse plant family on Earth, the Orchidaceae lack a definitive fossil record and thus many aspects of their evolutionary history remain obscure.

Here we report an exquisitely preserved orchid pollinarium (of Meliorchis caribea gen. et sp. nov.) attached to the mesoscutellum of an extinct stingless bee, Proplebeia dominicana, recovered from Miocene amber in the Dominican Republic, that is 15–20 million years (Myr) old. This discovery constitutes both the first unambiguous fossil of Orchidaceae and an unprecedented direct fossil observation of a plant–pollinator interaction.

By applying cladistic methods to a morphological character matrix, we resolve the phylogenetic position of M. caribea within the extant subtribe Goodyerinae (subfamily Orchidoideae). We use the ages of other fossil monocots and M. caribea to calibrate a molecular phylogenetic tree of the Orchidaceae.

Our results indicate that the most recent common ancestor of extant orchids lived in the Late Cretaceous (76–84 Myr ago), and also suggest that the dramatic radiation of orchids began shortly after the mass extinctions at the K/T boundary. These results further support the hypothesis of an ancient origin for Orchidaceae.