The presence of wild orchids has little to do with chance; it depends on several factors like the period of the year, the composition of the ground, its richness, its percentage of moisture. All are important parameters favouring the presence of certain orchids or make impossible the growth of others. Altitude, light and latitude are also to take into account.

To find flowering orchids, it is first necessary to choose the season of observation, April to June is the most favourable period, however, the period of flowering can be different according to latitude and altitude. Then the nature of the ground should be studied, if it is calcareous, open and located rather at the south, and then the probability of finding orchids is particularly high! Indeed most of the orchids like limestone and sun. In a wet mountain meadow, the chance to discover a high number of species is rather strong particularly Dactylorhiza.

Road edges also are an excellent field of observation. The sides are often well maintained and sometimes enriched with chalk brought during the road construction. While walking along the roads, a considerable number of Orchids species can be seen without difficulty: Ophrys, Cephalanthera, Serapias, etc.. Forests are poor in orchids, however wood edges offer much better occasions particularly for Epipactis or Platanthera.

Generally, finding orchids needs to explore the less trampled places, preferably upstream of the cultivated fields, where fertilizer concentration is minimal.

Some general parameters influencing orchid populations.

Climate and latitude.

France comprises various climatic areas according to latitude, ocean proximity or presence of relief (cf climatic chart). In general, orchid density increases towards the south; factors such as temperature and sun are probably responsible for this gradient. The greatest density is located around the Mediterranean sea with lots of Ophrys such as O. arachnitiformis, O. aurelia, O. bombyliflora, O. catalaunica, O. ciliata, O. drumana, O. incubacea, O. magniflora, O. provincialis, O. tenthredinifera, or such as Orchis olbiensis and Himantoglossum robertianum that even grows close to Lyon. Finally Anacamptis champagneuxii and papilionacea as well as Serapias neglecta and olbia are also to include in the Mediterranean species.

Atlantic Ocean exerts a considerable influence on the French climate and also, consequently, on presence of orchids. If Epipactis phyllanthes and Ophrys santonica and vasconica are regarded as typical species of the warm oceanic climate, a great number of relatively thermophilous species are acclimatized to Atlantic areas as well as to Mediterranean areas. The following species are in this case: Anacamptis coriophora subsp. fragrans, Anacamptis laxiflora, Dactylorhiza elata, Limodorum trabutianum, Neotinea maculata, Ophrys passionis Serapias cordigera, parviflora and lingua.

On the opposite, certain species do not reach the Atlantic side and remain subjugated to continental climate. Among those, are several mountain species accustomed to rigorous winters: Cephalanthera damasonium, longifolia and rubra, Dactylorhiza majalis, ochroleuca, Epipactis atrorubens, leptochila microphylla, muelleri and placentina, Orchis anthropophora, militaris and purpurea, Gymnadenia odoratissima, Ophrys fuciflora and Traunsteinera globosa.

Although it is less rich, North is not deprived of orchids. Several orchids are to be sought such as two subspecies of Dactylorhiza maculata: elodes and ericetorum, as well as Dactylorhiza praetermissa and sphagnicola and, in the littoral dunes, Epipactis neerlandica.

Sun and light.

Most of orchids prefer a high light level, therefore they grow in open sites. These orchids, also called heliophilous, are mainly Ophrys, Gymnadenia, Anacamptis an most of Dactylorhiza. Himantoglossum robertianum, Chamorchis alpina, Traunsteinera globosa are also avid of light. At the opposite, certain Epipactis, in particular E. purpurata, as well as Corralorhiza trifida, Listera cordata, Epipogium aphylum, Goodyera repens and Neottia nidus-avis have a clear preference for the shady areas. Epipactis helleborine or distans or even Orchis olbiensis, provincialis or spitzelii are generally found in scattered woods. Thus in badly maintained areas, where shrubs and bushes grow, orchid population decreases overall. The regular mowing allows to maintain the populations of heliophilous orchids. It is a simple and effective mean of protection.

Altitude

Altitude obviously involves a reduction of average temperature as well as an increase in the rainfall. However relief can affect the wind pattern and create particular conditions of shelter as well as wet or dry conditions according to their position with regard to the sea (cf the French relief map).

Many orchids are tolerant to altitude and some have a clear preference for mountain: Cypripedium calceolus, Goodyera repens, Epipactis distans, Listera cordata, Orchis pallens, Orchis spitzelii and Traunsteinera globosa. Numbers of Dactylorhiza also like mountain such as D. alpestris, angustata, cruenta, ochroleuca, parvimajalis, sambucina, savogiensis and viridis.

There is no doubt that champions of altitude are Nigritella (Gymnadenia) and Chamorchis alpina that can be found on the alpine level.

Finally some species do not endure altitude, it is precisely the case of Anacamptis palustris, Liparis loeselii, Spiranthes aestivalis and spiralis.

The ground.

Most of orchids are present on rather poor or oligotrophic substrates. If the ground becomes richer (eutrophication), after fertilizing for example, orchids lose their selective advantage and are quickly replaced. However certain species such as, for example, some Epipactis and Listera ovata are more tolerant and can be found even in humus of shady woods.

The ground physicochemical characteristics play a very important part. A great majority of orchids prefer a calcareous or alkaline ground. A good way to evaluate the presence probability of orchids in the prospecting place is to consult the area geological map: if the ground is calcareous, hunting will be much better! However certain orchids tolerate more acidic grounds and even some of them, very few, have a clear preference for acidity and thus grow on a crystalline or siliceous ground. It is the case of Dactylorhiza maculata subsp. elodes, D. sphagnicola, Hammarbya paludosa, Listera cordata and some Serapias, particularly S. neglecta.

Importance of water.

Although arid environments are poor in orchids, a rather great number of species can be found in the dry areas. It is noteworthy that low rainfall years are not favourable to observation. The majority of Ophrys and Orchis and also Spiranthes spiralis and Himantoglossum hircinum like dry places very much.

Conversely, certain orchids are to be sought exclusively in the places with strong moisture, such as Dactylorhiza, Anacamptis palustris and laxiflora as well as Spiranthes aestivalis. The peat bogs that are characterized by extreme moisture are also particular substrates. The alkaline peat bogs, presenting calcareous water, can shelter the discrete Liparis loeselii or several Dactylorhiza such as D. alpestris. Waterlogged acidic peat bogs host some Dactylorhiza such as D. sudetica or D. sphagnicola as well as the very rare Hammarbya paludosa that is probably the champion of moisture.
Generally, the hygrophilous orchids already very few, are particularly threatened by the draining of marshes wetlands and peat bogs.