The flora and mycobiota of Ukraine comprises over 17 ths species: mushrooms – 5 227, lichens – 1 322, algas – 4 908, bryophytes – 763, and vascular plants – 6 086. The vegetation combines 3.5 ths plant associations. The variety of plant is determined both by climatic and edaphic factors. Among climatic factors the leading role belongs to hydrothermal conditions influencing zonal (or altitudinal in the mountains) distribution of vegetation and limits of natural habitats of certain kinds, and among edaphic factors the humidity and nutritive value of soil are among decisive components. The antropogenic factor changes the distribution and structure of the groups of plants. In particular, over one half (65%) of the territory of Ukraine is under farmland and urban complexes; in certain oblast’s this index exceeds 90%. Although natural vegetation covers about 30%, it has been considerably transformed as well. Thus, forests occupy about 14% of the territory of Ukraine (together with the wind-forest strips – 15.6%); at the same time the similar index for Europe makes 41.3%. In Europe there are 1.3 ha of woodland per inhabitant, whereas in Ukraine there are only 0.2 ha. As a result of the continuous tree felling the overwhelming majority of forests changed their structure, composition and reduced productivity. The age structure of forests is as follows: saplings – 31%, middle age stand – 45%, ripening stand – 13%, adult and declining trees – 11%, while optimum correlation is 36:26:19:19. There are large areas of artificial monocultures.

Meadows (except for alpine and sub-alpine ones) replaced forests as a result of pasturing and mowing. The area of hayfields and pastures including meadows, steppes and partly bogs is 8.9%; it means 4% reduction during last 40 years. The resulting increase of the load of grazing and haymaking per hectare of land brought the productivity of meadows down.

Steppes, which potentially could occupy up to 40% of the territory of Ukraine, are fully ploughed up and stayed intact only at nature reserves, the area of which makes about 0.6% of the territory of Ukraine.

The area of bogs shrinked down to 1%, of flood plains – to 1,6%, of alkaline soils and salt marshes – down to 1%. Insignificant areas are occupied by azonal water plants, rupestral vegetation and psammophytes.

Ukraine is located within the limits of forest, forest-steppe, steppe and Submediterranean geobotanical zones.

The forest geobotanical zone includes western and northern parts of Ukraine. It has three provinces: Central European, East European and Carpathian-Alpine mountainous. East European province comprises Polissia and spurs of Middle Russian upland. Oak-fir forests prevail in Polissia, whereas hornbeam-oak and sometimes pine forests are found in its western part. As a result of tree felling and managed plantation their structure has changed: the monoculture of pine, secondary hornbeam, and lime in the eastern part became dominant here. Insignificant area of Polissia is occupied by secondary birch groves, which are formed on the sites of pine felling. The bottomland carries alder forests. The localities of European fir-trees are found in the northwest.

Polissia is characterized by relatively high swampiness; where swamps are represented by different types: oligotrophic, mesotrophic, and eutrophic. The oligotrophic swamps occur piecewise at the northwest watersheds; it is their southernmost location. These swamps are slightly domed; their sparse tree layer consists of deprimated pine and birch, and the sphagnum moss (Sphagnum magellanicum, S. cuspidatum, S. angustifolium, S. flexuosum) is the main edificator. Mesotrophic swamps are widespread on watersheds and secondary terraces of rivers; their stand consists of pine and birch, the moss tier includes sphagnum (S. fallax, S. centrale), grass includes harestail bog-cotton, wild pinkmary, cranberry, rannoch-rush, sedges (wool fruited, mud, beaked, black), white beaksedge, marsh cinquefoil, bogbean. Large areas of Polissia are occupied with eutrophic swamps, especially down the riverside. European alder, willows (grayleaf, laurel, eared), sedges (Bowles’ golden, acute, lesser pond), reed, water arum and hypnum bryophytes prevail here.

Polissia features both dry land and floodplain meadows. The former emerge on the felling sites carrying matgrass, red fescue, velvet bentgrass, gray clubawn grass (in the right-bank part). The following grasses prevail on the wet and maiden floodplain meadows: sheep fescue, smooth meadow grass and fowl meadow grass, meadow foxtail, lesser pond and acute sedges, common and path rush etc.).

The interstream Seim-Desna area belongs to Middle Russian subprovince of deciduary forest. This broken-relief upland carries forests with complex stands with prevailing small-leaved lime, Norway maple, ash, oak, etc.
The western oblast’s of Ukraine belong to the Central European province. In the deciduary forests here hornbeam-oak, oak and beech prevail; in Minor Polissia and Roztochchia they are joined by fir in poor edaphic conditions. This province is characterized by specific meadow steppes with prevailing dwarf sedge, Helictotrichon desertorum, Balkan moor grass, the dominance of which is determined by the presence of carbonates in soils and not by climatic factors. Relatively extensive areas are occupied by dry land meadows. The eutrophic swamps are widespread on the bottomland. Their main peculiarity is the presence of groups of brown bog-rush and Davell’s sedge, which grow on swamps with underlaying carbonates.

The Ukrainian Carpathians (Carpathian-Alpine mountainous province) are characterized by vertical humid-type zonality: foothill forest area, lower and upper mountain forest area, Subalpine and Alpine zones. Their altitude depends on the exposition of slopes and is considerably different on the southern and northern macroslopes. The foothill zone (up to 400–500 m asl) is characterized by the predominance of Quercus robus oak, sessile oak (in Zakarpattia (Transcarpathia), as well as hornbeam and beech forests. The way up (up to 1 200–1 300 m asl) there is the lower zone of beech and silver fir on the northern macroslope. The upper wood zone is located between 900 and 1 450 m asl on the northeast macroslope and 1 200 and 1 600 m asl on the southwest macroslope. On the glades the meadows are being formed carrying mat-grass, bent-grass, red fescue, feather reedgrass etc. Further up from 1 500 to 1 800 m asl) there is the Subalpine zone with the crooked forest: Swiss mountain pine, Duschekia Opiz and tall grass. The Alpine zone is at 1 800 m asl which only on Chornohora massif makes a continuous range while on other arrays it is fragmentary. The vegetation here includes low grass and bushes (three-leaved rush, Alpine azalea, evergreen sedge, Carpathian fescue etc.).

The forest-steppe geobotanical zone has three provinces: Pannonian, Ukrainian and Middle Russian. Forests occupy 13% of the area here. It is characteristic of the vegetation of Pannonian province a small fragment of which belongs to Zakarpattia (Transcarpathia) that it includes sessile and Dalechamps’ oak (together with South European kinds), and very degraded meadow steppes and steppificated meadows. The bottomland real meadows and swamps occur piecewise. The vegetation of Ukrainian province includes broad-leaved hornbeam-and-oak, oak and hornbeam derivate forests (on the right bank of the Dnipro River and fragmentary on the left bank) and linden-and-oak forests on the left bank. There is a considerable admixture of Norway, common and Tartar maple. In wetter and richer ecotopes one can come across the groves of tall ash and European alder along the streams. On sandy bottomland black poplar and willow forests are found, although rather damaged, and Russian olive on salinized bottomland. Other riverside terraces with coniferous forests bring pines and oak-pine forests as well as sharp-leaved willow thickets southward. The large flat areas with different chernozems, now under farmland, could be occupied by meadow steppes and sparse forests, the typical plant species of which could include Alpine meadowgrass narrowleaf, Wallis fescue, feather grass, golden feather grass and great feather grass. Such groups are but fragmentary. The wetter ecotopes are occupied by meadows with dominant cocksfoot grass, smooth meadow grass, red fescue and Festuca orientalis Kern fescue, and quackgrass. The bottomland meadows feature tufted hair-grass, meadow foxtail, and creeping bentgrass. This zone is characterized by eutrophic stream-bank sedge-and-rush and sedge-and-hypnum swamps. On the left bank there are fragments of saline lands and saline meadows.

The Middle Russian province includes maple-linden-oak woods and their derivates with the typical nemoral herbage (hairy sedge, goutweed, and sweet woodruff). The wetter conditions bring forth ash, alder forests and alder swamps. Typically the meadow steppes have group of dwarf sedge and other kinds of plants.

The steppe geobotanical zone occupies about 40% of the territory of Ukraine. Ukrainian steppes suffered unprecedented damage; therefore the steppe vegetation was preserved in limited areas only. The map shows the once existing vegetation, restored on the basis of surface soil characteristics. In the past the northernmost steppe had typical grassland-fescue-feather-grass vegetation on common chernozems, with prevailing of feather grasses Stipa lessingiana, great feather grass, Stipa capillaris, Wallis fescue and lush forbs. Bushes (blackthorn, European dwarf cherry, twin-flowered Cytisus, almond, meadowsweet etc.) could occur there quite often, and in gullies and ravines oak wood grew.

Further to south the subzone of fescue-feather-grass steppes formed on southern chernozems and chestnut soils. The physiognomically determining types of these steppes are xerophytic kinds of feather grasses Stipa ucrainica, Stipa lessingiana, Stipa capillaris. There are almost no shrubs and woods. In many undrainaged areas there are numerous catchments in the form of dishes and folds covered with meadow and meadow-saline-land vegetation.

In the Syvash region and the Black Sea coastal region the desertified sagebrush-and-grass steppes with solonetzs and salt-marsh land on saline chestnut soils had been widespread. In the valleys of major rivers (the Dnipro, the Danube, the Dnister, and the Pivdennyi Buh) tall-grass water-air and swamp groups of floodplains occur. The seashore solonetzs contain strips of halophytes with prevailing samphire, Halocnemum strobilaceum, Suaeda prostrata, Limonium meyeri, et al. The seashore spits feature halopsammophytes with wetland plants.

The Submediterranean geobotanical area includes the Crimean Mountains. It is characterized by the zoning of vegetation up to the mountain meadow steppes. The zoning of the southern and northern macroslopes is excellent. The lower part of the northern macroslope (up to 300 m asl) is occupied by the forest-steppe zone characterized by alternation of hemixerophilous pubescent oak forests and shibliaks with common steppes. The way up from 400–450 to 700–800 m asl there is the medium forest zone of nemoral sessile oak, hornbeam and ash forests. The upper zone (from 700–800 to 1 200 m asl) combines beech forests with inclusions of hornbeam, ash and maple.

The flat rolling highlands of the Main Ridge of the Crimean Mountains bear the zone of mountain meadow steppes including dwarf sedge, feather grass Stipa pellita Tzvel, Wallis fescue, Bromopsis cappadocica, meadows and bushes containing common rock pink, thymes, Teucrii herba, mountain germander and Genista albida, etc.

The upper forest zone of southern macroslope (from 800–900 to 1 200–1 300 m asl) included beech and pine forests (Crimean and cluster pines). The middle zone (from 400–450 to 800–900 m asl) includes Crimean pine and sessile oak forests; the lower one includes typical hemixerophilous Submediterranean forests of pubescent oak with sparse growth of tall juniper and Turkish terebinth.

In the SW part there are fragments of evergreen small-fruited strawberry tree. On the glades there are bushes (shibljak) and secondary ephemeral grassland.

The economic activity of man has changed the flora of Ukraine reducing the amount of valuable food and medical plants.

Annually they gather considerable volumes of 30–35 kinds of wild plants. During the last two decades the yields of such wild plants as juniper, Tormentil, marsh mallow, lily of the valley, white water lily, snakeweed, Greek valerian, stag’s-horn club moss, yellow pond-lily decreased more than ten times; certain plant species became scarce or not available. The natural resources of cranberry, marsh tea, and sweet flag are shrinking because of the large-scale lands drainage and intensive procurement. The natural resources of small goat’s thorn, mountain tobacco, and deadly nightshade are exhausted at present, and the species are registered in the Red Data Book of Ukraine; the spring Adonis and Spanish liquorice are included into regional conservation programs. The natural resources of wild and hairy thyme, common buckthorn, marjoram, caraway, common immortelle and buckthorn shrunk; the collection of this raw material from natural habitat must be limited.

The preservation of plants is also a topical problem. The Red Data Book of Ukraine (1996) registers 541 kinds of plants and mushrooms: vascular plants – 439 kinds, bryophytes – 28, algae – 17, lichens – 27, and mushrooms – 30. The Green Book of Ukraine (1972) including 127 different syntaxons is intended to preserve rare groups as important components of landscapes.

Alongside the reduction and disappearance of certain kinds and groups of plants there emerge adventive kinds joining seminatural and even natural groups.

The flora of Ukraine includes 830 adventive plants or 16% of all species. Twenty-nine species intruded during last 150 years; 24 of them are still continuing their rapid expansion: common ragweed, curly-top gumweed, hogweed, Himalayan balsam; sunflowers: Heliаnthus tuberosus, paleleaf woodland sunflower, woodland sunflower; Japanese knotweed, giant sumpweed, coastal sandbur, yellow starthistle, hawkweed ox-tongue, buffalo bur, and harmal. The naturalization is especially rapid in the case of North American and Asian plants, and most of all in the case of the Mediterranean group. The spread of adventive plants predetermines the rising amount of species, inclusion into plant communities, and corruption of the gene pool.