You need some chance to find French Bartsia (Odontites jaubertianus). It flowers only at the end of September and you can't call it exactly conspicuous. And it does not grow on the side of a walking path, it prefers less accessible spots like agricultural fields or wastelands. And when it does not have flowers, it really looks very much like other Bartsias.
It is endemic in France, it only grows here. It was thought that French Bartsia had disappeared from the Dordogne département. But no, at the boundary of a harvested field of cereals it still grows in crowds. Here a few dozens of plants, a bit hidden in the vegetation around it.
It looks very much like Yellow Bartsia, the same rather stiff reddish stems with small opposite leaves. Maybe French Bartsia is a bit stockier. There are French Bartsias with pale yellow or salmon pink flowers, sometimes mixed with plants with darker yellow and orange tinted flowers. This is normal, French Bartsia comes in two tones.
Probably because its forebears, Yellow Bartsia and Red Bartsia, have different colours. It is an allopolyploïd. Which means that, a long time ago during hybridization, the new species kept or even doubled or quadrupled all the chromosomes of its two ancestors. We think it has the possibility to show any of those colours and that every plant 'chooses' its colour according to circumstances.
The flowers are slightly more closed than those of other Bartsia species. Also a bit hairier, but you need a looking-glass to see that.