"This region is the home of many species of wildflowers."
"Many species of wildflowers can be found in this region"
Unless you're talking about a single specific species of wildflower.
"This species of wildflower can only be found in this region"
This feels correct to me.
There are some very confusing things online:
From the Woodmeadow Trust in the UK - www.woodmeadowtrust.org.uk
"Download our spotter sheet before you visit and see how many species of wildflower and grasses you can spot. "
they used a singular for "wildflower" but also used a plural for "grass".
The plural seems correct to me here.