Indigen
In general usage the word indigen is treated as a variant of the word indigene, meaning a native.
Usage in botany
However, it was used in a strictly botanical sense for the first time in 1918 by Liberty Hyde Bailey ((1858–1954) an American horticulturist, botanist and cofounder of the American Society for Horticultural Science) and described as a plant
Later, in 1923, Bailey formally defined the indigen as:
Botanical definition
The term was coined to contrast with cultigen which he defined in the 1923 paper as: