Silversword alliance

The silversword alliance, also known as the tarweeds,[1] refers to an adaptive radiation of around 30 species in the composite or sunflower family, Asteraceae.

The genus Dubautia contains a wide variety of forms, including cushion plants, shrubs, trees, and lianas.

[12] The last common ancestor of the silversword alliance was likely a mat and rhizome forming plant not more than .3 metres (0.98 ft) tall, with a chromosome number of 2n = 16, and perhaps another similar species.

How the silverswords' chromosome number arose is a matter of some uncertainty, but two major scientific theories have been proposed.

The hybrid then, by allopolyploidy doubled its chromosome number spontaneously, leading to the resultant and extant 2n = 14 species.