Most of plant life in the Tatras is considered Western Carpathian flora based on phytogeographical distribution. Only a small portion in the north-western part of the area is in the flora district of the Western Beskid Mountains (Western Beskid District) and in the north-eastern part of the area is in the flora district of the Eastern Beskid Mountains (Spišské Vrchy District). The flora of the Tatras is inside the Central High Carpathian flora district and specifically in two phytogeographical districts: Tatras and Sivý vrch. The Tatra massif is inside the Inner Carpathian Basin flora district (Podtatranské kotliny district and the Liptovská and Spišská kotlina sub-districts).

The size of the area, the large elevation differences and alternation between various geological substrates, specific climatic conditions and micro climatic conditions in the deep valleys, soil conditions and last but not least historical factors have influenced flora development in the Tatras and provide the means to support the existence and survival of a broad range of species in these areas. Species range from representatives of foothill and warm season species to wetland, forest, mountain and alpine species. The Tatras are home to nearly 1,650 species and varieties of algae and cyanobacteria, 1,200 species of lichens, more than 720 kinds of moss and liverworts, and 1,400 species of vascular plants. Many plants are only found in these areas in Slovakia or in the entire Western Carpathians (Tatra, Western Carpathian or Carpathian endemics): Tatra field locoweed (Oxytropis campestris subsp. tatrae), Campanula napuligera (Campanula serrata), Euphrasia tatrae, Tatra bellflower (Campanula tatrae), thistle (Carduus lobulatus), Festuca tatrae, Cerinthe glabra subsp. tatrica, Tatra scurvy-grass (Cochlearia tatrae), Tatra poppy (Papaver tatricum) and Tatra alpine Leucanthemopsis (Leucanthemum alpina subsp. tatrae).

Many glacial relics have endured here as well, some of which are at the southern-most limit of their range. Glacial relics, i.e. the descendants of flora from the Ice Age, present in the Tatras include: alpine bearberry (Arctous alpinus), Carex atrofucsa, chestnut rush (Juncus castaneus), three-hulled rush (Juncus triglumis), Elyna myosuroides, Dryas octopetala, Saxifraga retusa and glacial buttercup (Ranunculus glacialis).

Among other very rare species of plants found in the Tatras in one or a few places are Armeria alpina, Carex parviflora, Petrocallis pyrenaica and Pulsatilla vernalis.

Lichens 

Lichens represent a unique coexistence of fungal filaments with algae or cyanobacteria. The fungus absorbs water vapour to speed up the photosynthesis in algae and provides protection against sunburn. Lichens grow very slowly and live for many years. They successfully occupy habitat with climatic and soil conditions that are too harsh for higher plants. In the rocky and harsh climate areas, lichens can also act as the dominant plant communities and determine the character of the vegetation. In these extreme conditions they are an important source of nutrition for animals. Given the fact that lichens do not tolerate polluted environments, they are natural bio-indicators of purity. Lichens are also important in terms of soil formation as they excrete various organic acids and thereby undermine the bedrock. Lichens are found on the ground, rocks, walls, fences, roofs on the bark of trees and even on rotten wood. They attach to the substrate using adhesive fibres. Lichens reproduce sexually in rare cases; more common is reproduction using parts of the thallus, which may have a number of different shapes: 

crustose – cannot be removed from the substrate without damage 

foliose – attach to the substrate at multiple locations 

fruticose – attach to the substrate at a single location 

gelatinous – have a vague shape of jelly-like consistency

In the primarily spruce forests of the Tatras, lichens primarily grow as epiphytes on the trunks and branches of spruce or fir, larch and Swiss pine (Pinus cembra).

The most obvious are the species in the genera of Alectoria, Bryoria, Usnea and Evernia. Their twisted, branched thallus protrude out from thin branches and the trunks of trees, in particular near the upper elevation limit of the forest or in alpine valleys with frequent fog conditioning their optimal development. These species, however, are under the biggest threat and may possibly be a dying taxonomy. 

Tube lichen (Hypogymnia physodes) is the most widespread on tree trunks with its characteristic bubbly and puckered grey thallus with lobes on its ends.

Cladonia digitata is often found near the damper bases of trunks with grey to olive green thallus scales. Cupped sections are interspersed that divide into slender finger-like segments at their ends and red fruiting bodies at their ends.

Vibrant yellow Acarospora oxytona is characteristic on vertical, inaccessible walls in the Tatras. Species in the Rhizocarpon genus are responsible for the characteristic yellowish green colouration of granite rock.

Lichen vegetation is also diverse on periodically inundated rocks and boulders in mountain streams and lakes. Dermatocarpon luridum is dominant in these areas.

Bryophytes

Bryophytes grow on various substrates and in various conditions. Perhaps you have noticed them on various types of stone, on rotting wood, on the ground, on rocks, in streams and springs, on bogs, on forest humus and on tree trunks. Bryophytes are divided into two branches depending on the structure of the sporangia: liverworts and mosses.

The importance of bryophytes for nature and indirectly for humans is larger than it would initially appear. Many species inhabit rocks or surfaces that are disturbed as a result of erosion; in this case they help prevent undesirable landslides, which in turn creates better conditions for the growth of other species of plants. They provide shelter to invertebrates and are an important part of their diets.

Water is primarily drawn from the atmosphere and very little is taken from their substrate. They are able to retain a large quantity of water, equal to 2.5 times their weight. Given they often grow in large quantities, they hold a large quantity of water like a sponge and the subsequent evaporation of this water helps to regulate the climate in the area. They create a natural water reservoir, helping to protect the soil from drying out and keeping it moist. In bogs, mosses retain rain water that is then connected to waterways. This primarily involves sphagnum mosses (Sphagnales). Plant matter on the bottom dies while continuing to grow on the top. A thick layer of peat is formed in this manner over hundreds of years.

Short, dense, boule-shaped black, red and purple-coloured mosses are found as a result of the low temperatures at the high alpine elevations. The amount of light that bryophytes require is typically lower than vascular plants.

A group of Arctic-alpine species is characteristic for the Tatras, including liverworts Anthelia juratzkana, Lophozia opacifolia and Scapania degenii and mosses Brachythecium glaciale, Conostomum tetragonum, Dicranum groenlandicum, Grimmia holleri and Hygrohypnum polare.

Vascular plants

Large variations in elevation, extensive surface segmentation, diverse geology and different moisture and soil conditions in the Tatras support a variety of flora. Warmth decreases with increasing elevation, which results in the formation of a number of elevation vegetation zones from the foothills to the tops of the Tatra peaks. Each one of these zones represent a number of unique and different habitats for flora and other living organisms.

In the Tatras, the foothill (sub-montane) elevation vegetation zone reaches up to an elevation of 700 to 800 MASL and has been subjected to the strongest anthropic pressure throughout its historical development. It is largely comprised of agricultural land. Nuisance species (species introduced through human activity) are most widespread in this zone in landfills, on field roads, around residential areas, in fields and in gardens. Fields and meadows comprise a large portion of the Tatra foothills and the Tatra basins. Hay meadows, pastures, wet, fens-type and peat meadows alternated here in the past. Many of these meadows are currently affected by the intensification of agricultural production, reclamation and drainage. Ameliorative intervention devastated large parts of the bogs and swamps. The intensification of agricultural production had a negative impact on the species composition of the vegetation and the original, diverse communities were decimated. The remains of these were preserved in the foothills of the Western Tatras and in the cadastral territories of Važec, Východná, Pribylina and Liptovská Kokava, where several timber barns remain that were used to store hay that was brought down into the villages during the winter. Plant species here include devil’s-bit (Succisa pratensis), autumn crocus (Colchicum autumnale), goatsbeard (Tragopogon orientalis), oxeye daisy (Leucanthemum vulgare), Holcus lanatus, yarrow (Achillea millefolium), Centaurea jacea, meadow foxtail (Alopecurus pratensis), orchard grass (Dactylis glomerata), sweet vernal grass (Anthoxanthum odoratum), quaking-grass (Briza media) and spreading bellflower (Campanula patula).

Bogs and fens have undergone a tremendous change in recent decades. Bogs, as areas with high ground water levels that form peat due to the anaerobic decomposition of organic matters, were harvested in the area around Spišská Belá while others, in particular those in the Tatra foothills were drained (ameliorated). This action did add agricultural land, but also produced a large number of damp meadows, fens and swamps. The remains of the bogs are intact to a limited extent in the foothills of the entire Tatras. The largest fens-type bogs with a high number of species are the Belianske luky meadows, which are home to many protected and threatened species. Transitional bogs are the transition between fens and raised bogs and are found in the Tatras in the early stages of filled-in lakes and are found at the foot of the High and Western Tatras (Švihrová, Poš and Kút). Raised bogs themselves form in depressions with little to no drainage or filled-in lakes and represent the most precious and vulnerable form of bogs given that they are completely dependent upon atmospheric precipitation. These are then invaded by scrub and spruce, which then overgrow the entire area and the bog ceases to exist.

These areas are a suitable habitat for representatives of the Orchidaceae family and for species including bird's-eye primrose (Primula farinosa), trollius (Trollius altissimus), Pedicularis sceptrum-carolinum, common butterwort (Pinguicula vulgaris), Siberian iris (Iris sibirica), Menyanthes trifoliata and Scheuchzeria palustris.

Forest undergrowth in the montane vegetation zone (from 700 to 1200 MASL) includes various species of grasses, such as Calamagrostis villosa, white wood-rush (Luzula luzuloides), greater wood-rush (Luzula sylvatica) with various species of well-known herbaceous plants Majanthemum bifolium, Oxalis acetosella and Senecio nemorensis. In light-filled areas, clearings and the edges of the forest are marked with the bright purple flowers of fireweed (Chamaerion angustifolium) with several representatives of ferns in areas with boulders and damper substrate.

Low shrubs are widespread such as blueberry (Vaccinium myrtillus) and lingonberry (Vaccinium vitis-idaea), which reach up into the upper montane zone (1,200 to 1,500 MASL). Carpathian snowbell (Soldanella carpatica) is endemic to damp, humus-rich stands along with the important Carpathian endemic chrysanthemum (Leucanthemum waldsteinii). Rocky and in particular exposed areas on limestone are the perfect locations for forests with Sesleria varia, mountain cowslip (Primula auricula) and edelweiss (Leontopodium alpinum), which otherwise are only found in higher vegetative zones.