The flora of the Massif Central is rich and diverse. This diversity can be explained by the massif's large surface area, its position at the intersection of different climatic zones, and its geological variety. The plants that can be found in the very wet western part are not the same as those found in the drier eastern part, and the difference is even greater in the species that can be found in the southern part (Causses, Cévennes), which are subject to marked Mediterranean influences. This spatial component is not the only aspect involved, since exposure, altitude, and the nature of the substrate are also determining factors. For example, there is contrast between south-facing () and north-facing () slopes, and a difference in vegetation between acidic soils (granite) and basic soils (limestone or basalt). Although the altitude of the Massif Central is low compared to other mountain ranges such as the Alps or the Pyrenees, there is a clear range of vegetation, from Mediterranean vegetation to sub-alpine grassland (as is seen in the Cévennes). Generally speaking, in most of the Massif Central, there are four distinct levels of vegetation.
a lowland level up to 500 m altitude, well represented in Limagne a hill level, up to 900 m altitude in most of the massif, except in the north-west where this limit is lower a mountainous zone, up to 1,500 m altitude a subalpine zone, above 1,500 m altitude
In the Cévennes, the plain level can be described as the "Mediterranean level". These limits can vary according to exposure - for example, they are lower on north-facing slopes.
Lowland
Lowlands are relatively rare in the Massif Central, given its high plateaux, but are present on the Limagne Plain and in the Roanne and Montbrison basins. These are intensively farmed areas that include little natural vegetation. They also receive little water (the Limagne d'Issoire is one of the driest areas in France, with just over 500 mm of rainfall a year(fr) G. Joberton, Y. Perret, T. Dalbavie, Arbres et fleurs de nos montagnes, De Borée, 1991, p. 12) and are subject to a fairly marked semi-continental climate (more accurately, a semi-oceanic "intramontane" or semi-oceanic shelter climate in France), with hot summers and cold winters, due to frequent temperature inversions. Characteristic plants of this environment include downy oak (Quercus pubescens), Etruscan honeysuckle (Lonicera etrusca), sainfoin (Onobrychis viciifolia), meadow sage (Salvia pratensis), red poppy, red clover, wild pansy, common milkwort (Polygala vulgaris), yarrow, Persian speedwell and many others that are not specific to the flora of Auvergne.
The few small volcanic peaks that are scattered across Limagne are of ecological interest in that Mediterranean flora thrives on their southern slopes, where plantsBased on surveys carried out by the Conservatoire Botanique National du Massif Central (CBNMC). of clearly southern origin include Montpellier burclover (Medicago monspeliaca), morning glory (Convolvulus lineatus) and Montpellier astragalus (Astragalus monspessulanus).
In the Cévennes, the plains are covered by Mediterranean shrubland, dominated by holm oak.
Hills
This level is more often forested than the lower level. The characteristic trees at this altitude are the Sessile Oak and the Pedunculate Oak, especially in the west of the massif. In the east, the Scots pine can be found.G. Joberton, Y. Perret, T. Dalbavie, op. cit., p. 16 Classic woodland flowers such as Lily of the Valley, Wood Anemone, common cow-wheat and Solomon's Seal can be found here. Slightly less common plants include the Stinking hellebore or Bear's foot, a plant that is easy to recognize and characteristic of basic soils (especially limestone). In the nineteenth and twentieth centuries, this level was the subject of massive reforestation, primarily in the Limousin region where conifers were planted, but also in the south on certain steep slopes which tended to erode, such as the black pine forests all around the causses and in particular in the upper Lot valley around Mende.
There are some areas of ecological interest, such as the Planèze of Saint-Flour, where relatively rare flowers of continental origin (Veronica spicata) and Atlantic origin (Ranunculus nodiflorus) can be found in the same place. Similarly, in the Puy-en-Velay basin, it is possible to find segetal species (those linked to cereal fields) of oriental origin, such as Conringia orientalis and Neslia apiculata. The Grands Causses region also has a flora of great interest, due to its particular geology and location, which is characterized by a strong spread of Mediterranean flora as well as the presence of plants from steppe and limestone mountain environments (see below).
Also of note is the presence of a carnation endemic to the Massif Central: the granite carnation (Dianthus graniticus) which, as its name suggests, grows on siliceous soil in the Cévennes and Vivarais up to an altitude of around .
Mountains
Forest
At , the beech forest begins, with its highly characteristic flora. Beech dominates at this altitude, being a large part of the western half of the massif. In the east, particularly in the Haute-Loire, beech is replaced by Scots pine, due to the drier climate. In some cold, damp areas, fir is mixed in with beech and may even become dominantG. Joberton, Y. Perret, T. Dalbavie, op. cit., p. 15, such as in the Monts du Cantal, Artense, northern Margeride, Forez mountains. It is at the mountain level that the Massif Central begins to stand out from the lowlands that surround it for the great richness of its flora. The species found vary depending on whether the woodlands have a basaltic subsoil (basic rock) or a granitic subsoil (acid rock). In the former locations, there are calcicole flowers, such as the very precocious Snowdrop, Montane knapweed, February daphne, yellow thistle, Five- or Seven-leaved Cardamine and Cacaliaster Groundsel. Sometimes, paradoxically, there are calcifugous species, due to the relatively neutral nature of basalt, which contains little silica or calcium carbonate in a natural state, these elements being in the form of silicates.(fr) F.Nouyrigat, Fleurs et paysages d'Aubrac, Du Rouergue Editions, 1998, p. 15 On granite, on the other hand, there are no calcicolous species. Acidophilous species include wood ragwort (very common in Forez), Prenanthes purpurea, common cow-wheat, and small cow-wheat. However, the vast majority of flowers thrive in both types of soil: Sweet woodruff, Martagon lily, two-leaved cornflower, Snow-white wood-rush, common foxglove, Herb Paris, Austrian Doronicum (Doronicum austriacum), Alpine squill, Pyrenean squill (west of the massif), whorled Solomon's seal, and Large-flowered Calament ("Aubrac tea"). Climatic influences also play a part: for example, rare plants with an Atlantic affinity such as the Welsh poppyG. Joberton, Y. Perret, T. Dalbavie, op. cit., p. 183 (Meconopsis cambrica) can be found in the forests of the western part of the massif.
All these plants are found in the Beech zone, especially on the edges of woods or in clearings, as beech woods are very dark, which prevents the majority of plants from growing, or in hazel coppices, but some of them can also be found in the Scots Pine zone. However, since pine forests are lighter, they are home to more plant species, particularly shrubs such as Common Juniper and mosses.
Finally, foxglove and fireweed, pioneer species that sometimes colonize large areas, are very common in woodland cuttings, often accompanied by trees or shrubs such as Birch, Black Elder (altitude < 1,200 m), Red Elder(fr) F. Nouyrigat, Fleurs et paysages d'Aubrac, Du Rouergue Editions, 1998, p. 108 (rare below 1,000 m altitude) or, more commonly, Scotch Broom.
Open areas
In the Massif Central, the open spaces of the mountainous regions are all man-made. There are three main types: pastures on volcanic mountains, which are very rich both ecologically and agronomically; moors or grasslands on granitic or schistose soils, which are less interesting agronomically but very rich in species; and finally, hay meadows. Within heathland, several sub-categories can be distinguished:G. Joberton, Y. Perret, T. Dalbavie, op. cit., p. 122 heathland with fern, purgative broom, callune or common bilberry (the latter two are generally found on thin granite soil). In addition, as moorlands are transitional areas between pasture and forest, they are often home to native tree and shrub species including birch, wild rose, hazel, hawthorn, rowan and whitebeam.
Boundary hedgesG. Joberton, Y. Perret, T. Dalbavie, op. cit., p. 105 (where they exist, as bocage landscapes are fairly rare in the Massif Central) also include some interesting woody species such as Common Ash (which is often severely pruned, as its leaves are used to feed livestock), Norway maple, Sycamore maple, blackthorn, raspberry and black birch, a shrub with white flowers that only grows at a certain altitude.
In terms of the herbaceous layer, grasses make up most of the plant cover, with a large number of species represented. The most common, particularly in acidic grassland and moorland, are orchard grass, tall wheatgrass, red fescue, common bentgrass, and stiff spurge; grassland dominated by stiff spurge is known as narda. There are also a number of species that are more typical of high-altitude pastures or heaths, such as sweet vernal grass, wavy hair-grass (Deschampsia flexuosa), broadleaf bluegrass and field fescue (Festuca arvernensis), the latter being endemic to the Massif Central and found in broom heaths.
As for the other flowering plants, they are distributed to varying degrees in all three types of open spaces. For example, there are species that can grow equally well in all three areas: yellow gentian, dog's tooth (in the western mountains), narcissus, elder-flowered orchid, European white hellebore, and mountain arnica. Others prefer mown meadows, such as Spiked rampion, Bistort, Poet's daffodil. Others are more often found in unmown pastures (whether granite or basalt), such as Petty whin, hairy greenweed, field gentian, Pulsatilla rubra (which is endemic to the Massif Central and found mainly on the eastern slopes of the various massifs), Meum athamanticum (also known as cistre, this plant is grazed by Salers or Aubrac cows and is responsible for the flavor of Cantal cheese), Irish Euphorbia (an Atlantic plant found in the west of the massif), Pyrenean Dandilion, and Conyza-leaved hawksbeard.
Finally, forming a transition between dry meadows and peat bogs, peaty meadows can occupy vast areas,https://inpn.mnhn.fr/docs/cahab/habitats-declines/6410_11.pdf archive especially on plateaux such as Aubrac or Cézallier. This is the domain of the Tufted hairgrass (Deschampsia cespitosa) and the purple moor-grass (Molinia caerula), plants accompanied by various species of rush (Sharp-flowered rush, Juncus conglomeratus) and a few other characteristic plants such as Sneezewort, Devil's-bit scabious, and red-brown clover.
Wetlands
Wetlands can include a number of biotopes: riverbanks or lakeshores, megaphorbs and peat bogs.
In megaphorbs, the plants are often tall (between one and two meters) and sometimes arranged in tight colonies, such as Aconitum lycoctonum subsp. vulparia, Garden monkshood (altitude > 1,200 m, highly poisonous), Siberian columbine meadow-rue, Bachelor's buttons, Adenostyles alliariae (alt. > 1,200 m), Wild Angelica and, more rarely, Carduus personata. These mountain plants can occasionally be found alongside plants such as Kingcup, Meadowsweet, or Valerian officinalis, which are common in the Massif Central in this type of ecosystem. As far as trees are concerned, the water's edge is often home to Black alder and various willow species, including some that only grow in the mountains, such as Salix pentandra and Salix bicolor.