Botanic Gardens Trust, Sydney, Australia

 

Poales - assembling the monocot tree of life

Barbara Briggs and Gwen Harden - Honorary Research Associates
 
Monocotyledons are a major group of flowering plants, including grasses, palms, sedges, lilies, orchids and much more. Within monocots, the most important as food sources for humans are the grasses: the source of wheat, corn, rice, cane sugar and fodder for animals. Grasses comprise the family Poaceae and, together with related plant families, such as Restionaceae and Cyperaceae, they make up the Order Poales.

For several years Barbara has been part of an international collaboration to determine evolutionary relationships within the monocots worldwide. This has involved researchers in many centres in the USA, Canada and Australia. They have based their findings on analyses of data from the whole of the chloroplast genome. Most of the DNA extraction and sequencing was done in the USA, but this required the collection and sending of representative species from many countries. Some of the collections sent for study were from joint fieldwork in north-eastern NSW with Honorary Research Associate Gwen Harden. Alex Floyd of the North Coast Regional Botanic Garden at Coffs Harbour also assisted with the fieldwork.

The first major paper from this collaboration has now been published in the Annals of the Missouri Botanical Garden. This reported on analyses of 81 chloroplast genes in 83 species, representing the families of Poales and its relatives. This gives a clearer picture than previously possible of the relationships of the families, including determining the closest relatives of the grasses. It also shows that there have been five separate events in the evolution of Poales when lineages have shifted from insect pollination to wind pollination, with associated changes in the structure of the flowers. These evolutionary changes also appear to be correlated with changes in the predominant habitats. Studies of relationships of other monocot groups are continuing.

Barbara Briggs & Gwen Harden
Honorary Research Associates Barbara Briggs and Gwen Harden collecting rainforest plants for the Monocot project. Photo: Alex Floyd

^Back To Top
Web CMS by Squiz