Hi Mark, and all, Others could define "clade" better, but in lieu of others, I'll try. A clade is a group of organisms, all of which are more closely related to each other than any of them is to any organism outside the clade. A clade may be a species, genus, family, or any other classical taxonomic level. A clade may also fall between the levels of the classical hierarchy. Does that help? Jim Shields not a taxonomist, in central Indiana (USA) At 10:19 PM 9/20/2005 -0400, you wrote: >What is a "clade"? > >Mark McDonough, antennaria@aol.com, http://www.plantbuzz.com/ ************************************************* Jim Shields USDA Zone 5 Shields Gardens, Ltd. P.O. Box 92 WWW: http://www.shieldsgardens.com/ Westfield, Indiana 46074, USA Tel. ++1-317-867-3344 or toll-free 1-866-449-3344 in USA