Spiranthes spiralis.
Spiranthe d'automne.
Autumn lady's tresses.
It's all in the name! The orchid blooms in autumn (late August to be exact...) and its inflorescence describes a spiral. It is both rare, except in certain departments in the south of France, and not very visible.
Orchid enthusiasts are less active in prospecting at the end of August, and it passes outside the usual observation periods. Sometimes, moreover, it flowers without warning: no announcing leaves, the stem emerges, the orchid flowers then disappears in about twenty days no more (experience). Discovering it is sometimes a matter of chance or thanks to a transmission between initiates. Given its particular needs in terms of biotope, it will sometimes find shelter in an urban area (untrampled but regularly mowed lawn, maintained cemetery edges, etc.)
In principle, the leaves are visible (but they must be noticed) before flowering.
The genus Spiranthes is widespread throughout the world and in both hemispheres, which is unusual among orchids (apart from inter-tropical species, of course).
Spiranthes spiralis and its "cousin" Spiranthes aestivalis are European and are found in France rather in the south but its presence is proven in many departments although rare. Spiranthes aestivalis likes more humid soils than Spiranthes spiralis which prefers fresh or dry calcareous soils. Morphologically, differentiating them will be extremely complicated moreover. A shift in the flowering date will add even more confusion: from there to suppose that there is only one species with early flowering localities...
Of variable size (between 5 and 30 cm), it will be found on grounds with short grass and thus will be visible despite its small size to an attentive observer.