Davidsonia, Vol 14 (3): 63-70 Figures: 1-3. Authors: Fred R. Ganders[super]1[/super], Brian Klinkenberg[super]2[/super], and Rose Klinkenberg[super]1[/super] [super]1[/super]UBC Herbarium, Department of Botany [super]2[/super]UBC Department of Geography Abstract: During conservation status report work on Bidens amplissima, many plants were found that resembled Bidens amplissima but lacked the trilobed leaves ascribed to the species. Herbarium investigations revealed that most plants with this form had been identified as Bidens cernua because of this lack of trilobed leaves. However, these plants more closely resembled B. amplissima than B. cernua in other leaf and achene characters. Multivariate statistical analysis of morphological characters from herbarium specimens unambiguously separated them into two groups. One group was Bidens cernua, and the other, including all the unlobed and trilobed-leaved specimens, was Bidens amplissima. Recognition of unlobed Bidens amplissima has resulted in an increase in the number of localities for the species, a range extension for the species into Washington State with its addition to the flora of the United States, and loss of its endemic status in British Columbia. This discovery was important for assessment of the status of Bidens amplissima and has broad conservation implications. Our results highlight the need for careful review of the taxonomy of species, particularly within difficult taxonomic groups, when conducting status assessments. Primary data re-evaluation may be critical where status designation has implications for both landowners and governments, and where conservation and protection policies are presently evolving. Supplementary links: Bidens amplissima in British Columbia Comparison of Bidens amplissima and Bidens cernua - please note that figures from the article are from this web site: Figure 1: Bidens amplissima. Unlobed leaf form. Figure 2: Bidens cernua. Figure 3: Achene comparison between Bidens cernua and Bidens amplissima.