The AquaPlant index contains references from many different plant sites. And several of these sites may contain the same plant. You can select if you want each reference in its own separate row, showing fields for the plant from that reference. Or if you want references to the same plant merged together into one single row. Such fill-in plant fields will be shown with a lighter background color.
Merged references give a more compact result, that is often easier to interpret for the beginner.
The advanced user will usually want the full information from each reference. Use references from You can select which sites you want references from in your search result. By default all sites are included. When there are more than one reference to the same plant, you can select that you want references from a specific site listed first. When there are more than one reference to the same plant, you can select that you want references from a specific site listed second.