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As first step towards building a model as Nicolas has suggested:<br>
I assume you have a layer with the county boundaries. Export this
layer as a CSV file, keeping only the name of each county in the
export step, and don't export the geometry.<br>
Now open this file in your spreadsheet app of choice.<br>
Add a new column for each plant species.<br>
Put a one in that column for each county where the species is
present.<br>
Save the file (still as CSV).<br>
<br>
Open the county layer and the new CSV files in Ggis.<br>
Open the properties window for the county layer and click on the
Joins tab.<br>
Click on the "+" to add a new join. Join to the CSV layer, and
select the county names field as the join field for each.<br>
<br>
Now your county layer has the plant species column.<br>
To display a single species, open the properties window for the
county layer, select symbology. Set the symbology as rule based. To
color just those counties with species 1, your rule would say
something like Species1 = 1, where Species1 is the field name you
used. Pick a color/transparency of your choice, then set the "all
others" rules to be the background color you want.<br>
<br>
That does it for one species. You can then export to tiff or
whatever. Getting it to cycle through all the different species is
for someone else to explain.<br>
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