Imagine that researchers are studying 2 populations of a hypothetical flowering

Question

Imagine that researchers are studying 2 populations of a hypothetical flowering

plant, Darwinius beardii.

Individual plants of population A grow to an average height of 25 cm, while those of population B average 40 cm. The flowers of population A are light purple and open in mid-April, while those of population B are dark purple with white spots and open in early May.

These 2 populations are geographically separated by a large river, and geological and molecular genetic evidence suggests that they have been separated for at least 10 million years, during which time evolutionary divergence has occured.

Yet, when individuals from each population are brought into the lab, they readily mate with individuals of the other population.

Under which species concept(s) would the plants of the 2 populations be considered the SAME species?

Science