Indigen
In general usage the word indigen is treated as a variant of the word indigene, meaning a native.
Wikipedia
Indigen (noun)
An indigene or native.
Indigen (noun)
A plant known to be indigenous to a region, rather than a cultigen. from 1918
“cultigen”
Indogen (noun)
A complex nitrogenous radical, C8H5NO, regarded as the essential nucleus of indigo.
Wiktionary