Existing phylogenies of living plants may or may not be supported by cladistic analyses. While some older phylogenies are supported by the new techniques, it some cases new and unsuspected relationships are discovered. Amborella is the most ancient living dicot. Native to New Caledonia in the Pacific,at present there is only one living specimen in the United States - at the Arboretum at the University of California at Santa Cruz. Acorus is sister clade to all monocots.
Legumes show highest diversity in the tropics of Africa and South America.
Most North American legumes are derived from European origins. North American plants show both stasis and rapid evolution. Cladistic phylogeny is attempting to integrate data from classical morphology, biochemistry, and palaeobotanical sources. The many linkages between terrestrial higher plants and geology have a long and colorful history. The first real scientific contributions were made during the first part of the 19th century.