|
|
|
|
The red and yellow pea-flowered shrubs of the Mirbeleae are a conspicuous element of the sclerophyll heaths, woodlands and eucalypt forests of Australia, especially in the south-west and east. Together with the Bossiaeeae, they comprise a natural group related to the great temperate herbaceous radiation that includes garden peas, beans and clover. However, it is clear that the Mirbelieae-Bossiaeeae have evolved in isolation for a long period in Australia, and the group is endemic on the Australian continental craton. Altogether there are about 700 species in 30 genera. See some of our publications on this group.
Recent unpublished phylogenetic studies by myself and collaborators using DNA sequences from both the chloroplast and nucleus, as well as traditional morphological characters, have supported that the Mirbelieae and Bossiaeeae together form a monophyletic group. These two tribes have been distinguished by the arrangement of their 10 staminal filaments: free in Mirbelieae and fused into a sheath in the Bossiaeeae. The reconstructed phylogeny strongly confirms the Bossiaeeae as a monophyletic group, but nests this lineage within the Mirbelieae, close to Gompholobium and Sphaerolobium. This relationship has the support of embryology - these genera share with Bossiaeeae much enlarged antipodal cells in the embryo sac. Most genera of the Mirbelieae lack antipodals altogether, but produce multiple embryo sacs, which is a unique feature in the legumes. The multiple embryo-sac group forms a clade in the phylogeny.
Below is an informal classification of the Mirbelieae and Bossiaeeae, based on the phylogeny, emphasizing the embryo sac types. The links in the table (also in the phylogeny) take you to pages on every genus, including the text to be published in the "Legumes of the World" book and some illustrations.
Giant antipodals group
Multiple embryo-sac group
|
|