My survey contains a list of 125 plant species. The user selects plant species along transects and counts the # of of each. In my 'count species' function, every time a species is counted, it registers as 1. If the same species is counted multiple times, it is counted multiple times, inflating my final species count. I need to only count the unique species selected from the list to get an accurate result. Is there a way to do this?