The information on cormophytes in Macin Mountains, dating back from the period 1952-1972, outlines the existence of an increased diversity of these cormophytes, as compared to the rest of the country. 

The great variety of flora and vegetation in Macin Mountains is represented by more than 1.770 plant species that make approximately 50% of Romania’s flora, growing on 1% of the country territory. Of these species, 72 are protected as they are rare or vulnerable and 27 species are endemic for the region.

Research works carried out on Pricopan Crest- one of the most representative as far as the xerophilous plants are concerned- showed there are 14 herbal association and 562 superior species fitting into 70 families, of which 72 taxons are threatened by extinction (they represent 5% of threatened species and are recorded on the “Red List of Superior Plants in Romania”).  

The fitotaxons’ importance in Dobrudja, as compared to the other rare plants in Romania, results from their composition, in which prevail the Pontic-Balkan (26,4%) and Pontic species (16,7%), to which also add species of Euro-Asian (12,5%), Balkan (11,1%), Mediterranean (8,3%), Mediterranean-Pontic (6,9%) origin, as well as other Caucasian, Asian, African and cosmopolitan species (18,1%).

The international importance of these rare taxons is conferred by the presence of the vulnerable taxon Campanula romanica (characterized by Dobrudjan endemism), of three rare European taxons Dianthus nardiformis (Pontic species), Centaurea tenuiflora (Pontic-Balkan) and Centaurea gracilenta (Balkan) and 5 suben­demic taxons Corydalis solida (Balkan), Euphorbia nicaensis ssp. cadrilateri (Mediterraneean-Pontic), Moehringia grisebachii (Pontic-Balkan), Moehringia jankae (Pontic) and Silene cserei (Pontic), of which the first 4 taxons are nominated on the “Red European List” as vulnerable or rare species.  Of the 72 threatened taxons, 18 are rare for Dobrudja, 5 are rare for the Northern Dobrudja and one taxon - Cachrys alpina (Pontic-Balkan) is considered extinct from Macin Mountains.

Macin Mountains are considered an important centre of speciation, due to the intraspecific diversity and to the 11 local taxons identified so far in Romania. Macin Mountains stand for the genetic center for Euphorbia măcinensis, Corydalis dobrogensis and Herniaria glabra var. dobrogensis.

Macin Mountains represent the northern limit of the sub-Mediterranean zone of the Balkan Peninsula and make a distinct unit of the floriferous Macedo-Tracian province. The bio-geographical importance of Macin Mountains also results from the interference of species that originate from different geographical zones. This is the zone of interference for the southern limit of Central-European and Caucasian species (Scutellaria orientalis, Stipa ucrainica etc.), the northern limit of the Mediterranean, Balkan and Pontic species (Silene compacta), the western limit of the Euro-Asian species Potentilla bifurca and of other rare species threatened by extinction. Macin Mountains also represent the only territory in the world where one of the rarest vegetal associations in Romania, Gymnospermio altaicae - Celtetum glabratae (with Celtis glabrata species) can be found and is under strict protection. 

About 200 years ago, the northern part of Dobrudja was covered with century-old oak forests of high productivity, whose development capacity would decrease only on northern rocky crests and on the land strip close to the central steppe in Dobrudja. The Dobrudjan forests underwent major structural changes, both before 1878, during the Turkish occupation, when valuable oak forests were exploited and after 1878 (the year that Dobrudja united with Romania), when two agrarian reforms were applied. Due to these reforms, large forest zones were turned into farming fields and common pastures and the remaining forest zones were seriously affected by the human activity (grazing in the forest, repeatedly applying the coppice-system with coppice and root-suckers regeneration, setting fire, etc.). Because of these negative actions, from 1850 to1930 the Dobrudjan forest surface decreased by approximately 63.000 ha (around 40.000 ha in Tulcea County) and at present, forests represent only 12% of the county territory.   After 1930, there would be a turning point in the Dobrudjan forest management which took shape in adopting the high-forest system (regeneration from seeds), forbidding the grazing in the forest and the cutting of trees in excess and at random, ecological reconstruction of the degraded stand with valuable forest, etc. Following this, between1950-1990 works of ecological reconstruction were carried out on 1.380 ha in MMNP and works of soil amelioration for large areas of deteriorated land.

What is characteristic to MMNP is the prevalence of the forest ecosystems, which ensures the ecologic stability and the optimum habitat for special herbaceous species that grow on this territory. The zone is characterized by a rich and unique biodiversity, which includes complex forest, steppe and forest-steppe ecosystems.

             Forests in MMNP are mainly formed by mixed broad-leaved stand in which sessile oak is the prevalent species in the north of the park and white/greyish oak is the predominant species in the south.  

             There have been identified 30 forest types in MMNP, installed on 15 forest sites with different qualities (72% with medium productivity, 21% with high productivity and 7% with low productivity). Vegetation conditions are also variable, fact which allows the presence of a high number of species and typical ecosystems. What is characteristic to MMNP is the presence of some forest types which can be identified only in this zone: Dobrudjan hill mixed hardwood forest, Dobrudjan mixed hardwood plain forest with greyish oak, forest-steppe mixed hardwood forest with sessile oak, plain greyish oak on degraded Chernozem, plain white oak, white oak with oriental hornbeam, sessile oak with smoke tree, normal sessile oak with oriental hornbeam, Dobrudjan beech-hornbeam with Carex pilosa, etc.  Macin Mountains comprise the following altitudinal zones and plant layers: the marginal Pontic-Balkan steppe, the forest-steppe with sub-Mediterranean forests, the xerothermal sub-Mediterranean forests and mesophilous hardwood forests.  

Here, there have been identified 6 rare forest vegetal associations at national level (4% of Romanian ecosystem types, Donita, 1970, 1990). The most frequent forest association -Tilio tomentosae - Carpinetum betuli, which is spread on 65.000 ha (about 1% of the forest zone), is representative for the park; the rarest and most unique forest type in Romania is the association of Dobudjan beech-hornbeam mixed forest and Carex Pilosa (Beech Valley-Luncavita). The association Tilio tomentosae - Carpinetum betuli, together with the associations Nectaroscordo - Tiletum tomentosa and Galantho plicatae - Tiletum tomentosae – spread only in the Northern Dobrudja and Fraxino orni - Quercetum dalechampii – specific to Dobrudja and Banat – were not identified in the neighboring European countries and can be considered endemic for Romania.

Another rare forest phytocenosis, existing on limited areas in Romania (in Dobrudja and on Buzau Hills) is the association Tilio tomentosae - Quercetum pedunculiflorae (Doniţă, 1970, 1990, citat de Petrescu, 1997).

             The tree association dominated by Spiraea crenata (threatened species) is another national rarity. 

             The most predominant forest phytocenoses are those specific to the west-Pontic forests of white oak (Quercus pubescens), Oriental hornbeam (Carpinus orientalis) and flowering ash (Fraxinus ornus), with  Paeonia peregri­na, Asparagus verticillatus and Pyrus elaeagrifolia, followed by Western-Moesian Pontic forests of sessile oak (Quercus polycarpa, Q. dalechampii, Q. petraea), hornbeam (Carpinus betulus), silver lime (Tilia tomen­tosa), with Fraxinus coriariaefolia, Nectaroscordum silicum ssp. bulgaricum, mixed with forests of sessile oak, Oriental hornbeam, silver lime and other xerothermal  forests. Forests of white oak, hornbeam and flowering ash which in the past used to represent the layer of sub-Mediterranean forests grow on low hills (150-250m altitude) made of plateaus, rounded crests, large valleys and slightly/medium inclined hill sides. The stand growing on the crests and sides is mainly formed by white oak, while the stand growing on valleys is formed by greyish oak.  The stand is formed by several vegetation layers: the upper layer, mainly formed by Quescus pubescens and disseminated from Q. polycarpa, Q. pedun­culiflora, Q. virgiliana; the intermediate layer is formed by Carpinus orientalis and Fraxinus ornus, with scarce Acer campestre, Sorbus torminalis and Pyrus pyraster and the inferior layer, very well represented by  Cornus mas, Crataegus monogyna, Ligustrum vulgare, Cotinus coggygria etc. The herbaceous cover is represented by southern species (Mercurialis ovata, Lithospernum purpureo-caeruleum, Carex hallerana, Paeonia peregrina etc.), in association with forest grasses (Brachypodium sylvaticum, Dactylis poligama, Melica uniflora etc.).

The Moesian western-Pontic forests of sessile oak, hornbeam, silver lime can be seen on the highest altitudes in Northern Dobrudja (over 250m), on hilly relief, with large ridges, plateaus or high sides, narrow valleys or relief with mountain aspect, crests and strongly inclined sides. The stand which belongs to the predominant species of Tilio tomentosae-Carpinetum betulis, grows on the valleys and on northern sides, seldom on plateaus and crests, on forest grey/brown soils, in the depth or mid-depth. The upper part of the tree layer is dominated by sessile oak (Quercus petraea ssp. dalechampii, ssp. petraea şi ssp. polycarpa), silver lime (Tilia tomentosa), European ash (Fraxinus excelsior, F. coriarirefolia), elm (Ulmus glabra) etc., while the lower part is represented by hornbeam (Carpinus betulus), lime (Tilia cordata, T. platyphillos), flowering ash (Fraxinus ornus), common maple (Acer campestre) etc. The shrub layer is formed by cornel tree (Cornus mas), hazelnut (Corylus avellana), common hawthorn (Crataegus monogyna, C. Pentagyna) and spindle-tree (Evonymus verrucosa). The herbaceous layer, which is not so well developed, is represented by Brachypodium sylvaticum, Dactylis polygama, Geum urbanum, Polygonatum latifolium, Lathyrus niger, Viola hirta etc., in association with Central-European species (Cardomine bulbifera, Galium odoratum, Carex digitata, Anemone ranunculoides, Hedera helix, Mercurialis perennis etc.).

Habitats with skeletal soils, as well as forest steppe habitats are the places to identify vegetal phytocenoses belonging to the association Nectaroscordo-Tilio tomentosae, in which sessile oak is associated with lime tree, flowering ash, Oriental hornbeam (Carpinus orientalis) and European ash (Fraxinus excelsior, Fraxinus coriarirefolia) etc. The shrubs are represented by cornel-tree, common hawthorn and common privet, while the herbaceous layer is dominated by southern species (Nectaroscerdum silicum ssp. bulgaricum, Lychnis coronaria, Arabis turrita, Lythosmermum purpureo-coeruleum, Mercurialis ovata etc.).

In the vicinity of the forest steppe, on deeper soils, sessile oak is replaced by greyish oak, within the vegetal association Tilio tomentosae - Quercetum pedunculiflorae).

             The stand in MMNP has the following characteristics:

- the great biological diversity of the 67 ligneous species, of which we mention the genera: Quercus (7 species), Tilia (3 species), Acer (3 species), Ulmus (3 species), Carpinus (2 species), Fraxinus (3 species), Fagus(2 species), Malus, Celtis, Juglans, Prunus, Sorbus etc., as well as many shrub species (Corylus, Rosa, Lygustrum, Cornus, Sambucus, Lonicera, Cotinus, Paliurus, Crataegus, Viburnum, Spiraea etc.);

- the natural character of forest ecosystems on a large area (42% fundamental natural stand), and those partly derived (18%) and completely derived (29%) keep in their composition the local species, which ensures the conservation of the biggest saxicole vegetation in the country, vegetation that comprises the majority of species threatened by extinction, which are quite rare at the national level;

- the increased presence of lime tree (36%), European hornbeam (12%) and Oriental hornbeam (7%) in the general composition of forests, to the disadvantage of the main species – sessile oak and oak, which were primarily and selectively cut in the past, aspect that imposes the ecological reconstruction of all derived stand which is degraded and scarcely productive;   

             - the imbalance of the age classes of stand, with young and middle aged stand predominating and a lack of mature stand which could be pre-logged and logged;

- the high consistence of stand (90% of the stand area with normal of full consistence), which guarantees the protection of land and soils against erosion and – implicitely – the specific flora and fauna; 

- the low productivity of stand in comparison with the medium quality of forest sites, which can be explained only because of the selective and repeated harvesting of species that are valuable from the economic point of view (sessile oak, oak, ash); this low productivity also results from the coppice logging of forests, with their vegetative regeneration, which contributed to the stand invasion  with lime trees, European and Oriental hornbeam and to the degradation of the forest ecosystem composition, etc. 

It has to be mentioned that, although a part of the forests have their normal composition and structure modified, they conserve the local herbaceous species, representative for the Pontic steppe of Dobrudja, which in Romania can be spotted on small and dispersed areas. The list of species of conservative interest is presented in Annex 2.3.1.