| A vascular plant inventory of Rio Grande National Forest (RGNF) and San Juan National Forest (SJNF) and vicinity, constituting approximately 5,000 mi2, was conducted in 2003 and 2004. A total of 11,019 specimens were obtained documenting 1,069 unique taxa in 90 plant families. An additional 191 unique taxa from past collections contribute to a total of 11,405 taxa for the area. A total of 46 species of conservation concern, with 148 occurrences (116 from this study), and 18 endemics were documented. In addition, 114 non-native taxa having origins outside of North America were documented, of which 18 are designated as noxious weeds. Specimens have been deposited at the Rocky Mountain Herbarium (RM), with representative sets given to the RGNF and the SJNF. This thesis discusses the methodology and description of the study area including circumscription, climate, topography, drainage systems, geology, soils, and vegetative communities. Also provided is a discussion on species of special concern, noxious weeds, floristic comparisons with adjacent areas using So´rensen's index of similarity, and results. An annotated checklist was generated based on voucher data from the 1,265 unique taxa. Included in the checklist are the number of collections, counties of occurrence, location in relation to the Continental Divide, habitat type for each documented taxon, and elevation ranges. |
