The Vascular Flora of Boone County, Iowa (2005-2008)

A vascular plant survey of Boone County, Iowa was conducted from 2005 to 2008 during which 1016 taxa (of which 761, or 75%, are native to central Iowa) were encountered (vouchered and/or observed). A search of literature and the vouchers of Iowa State University\u27s Ada Hayden Herbarium (ISC) revealed 82 additional taxa (of which 57, or 70%, are native to Iowa), unvouchered or unobserved during the current study, as having occurred in the county. This total of 1098 taxa (979 species, 57 varieties, 39 subspecies, 23 hybrids) places Boone County first in vascular plant richness among 18 published county inventories conducted in Iowa. A checklist of Boone County vascular plants including scientific names, common names, and habitat data for all 1098 taxa is presented, and abundance data is presented for taxa encountered during the current survey. This study reports 56 taxa that are not included in the Checklist of the Iowa Vascular Flora (Eilers and Roosa 1994) including an unnamed species of Oenanthe L. (water parsley) that may represent a new species. Twenty-two taxa currently or historically known from Boone County are considered to be endangered, threatened, or of special concern in the state of Iowa (Iowa Administrative Code 2002). Of the 82 historic taxa not found ( missing ) in the current survey, the proportions associated to tree-dominated habitats (35%), prairie habitats (30%), wetlands (12%), and open habitats (23%) are different (p\u3c.01) than these same proportions in the vouchered and/or observed flora (tree-dominated habitats: 53%, prairie: 15%, wetlands: 8.5%, open habitats: 23%). Sites containing uncommon and/or rare plant taxa are mapped and listed. The results of this survey provide a more thorough evaluation of the habitat and abundance of the flora in Boone County and in Iowa. Furthermore, the extensive field work conducted during this study reveals the need for appropriate natural resource management (invasive plant control, removal of woody plants encroaching on prairie remnants, etc.) on select public areas in the county. Finally, this study reveals the need for a computer database of specimens in Iowa\u27s herbaria and an online, regularly updated checklist of Iowa vascular plants utilizing current nomenclature