Flora

The Alpine Squill is a so-called river corridor plant; its range is limited to river valleys at lower elevations. Along with the Snowdrop, the Alpine Squill is one of the first signs of spring in the Donau-Auen National Park.

Amphibious Bistort – also called Water Smartweed, especially in North America – is a very versatile plant which adjusts its form to the prevailing water conditions and levels. Depending on the site, this species may be found either on land or as a floating plant in the Donau-Auen National Park.

Arrowhead is a plant of many forms and has adapted ideally to the ever-changing conditions found in wetlands habitats. In deep waters, it forms narrow, ribbon-like leaves below the surface. Above water, it has floating oval leaves. The typical arrowhead-shaped aerial leaves are only formed when water levels are low. On very sunny sites, these leaves are arranged on a north-south axis, the Arrowhead functioning as a so-called compass plant.

The Autumn Crocus, also known as Meadow Saffron, is one of the most poisonous plants in the Donau-Auen National Park. Its large pale lilac flowers, which resemble those of the crocus at first glance, are a characteristic autumn sight of wetlands meadows. In fact, another common name for Colchicum autumnale is "Naked Lady" and has to do with the late blooming of the flower: where the autumn ground is bare and barren, this species flowers conspicuously and colourfully and all alone, when and where it is least expected. The fruit of the Autumn Crocus over-winters under ground and appears only in the spring along with the leaves of the plant.

The Bee Orchid is self-fertilizing, but it may be pollinated by insects (bees). In Lower Austria, the Bee Orchid is an endangered orchid species.

The Black Poplar is native to softwood riparian forests and lowland river valleys with gravel banks. It grows quickly and robustly and normally has a broad crown with irregular branch patterns. In ideal sites, Populus nigra may reach heights of around 30m and trunk diameters of 2m. Life span is approximately 100, but occasionally up to 300 years.

The Blackthorn is a widespread deciduous shrub of medium size with dense, thorny branches. With its well-developed root system, it propagates quickly by way of stump suckers and tillers, often forming dense, nearly impenetrable thickets which are ideal shelters for birds. In the Donau-Auen National Park, the Blackthorn's impressive masses of white flowers appearing before the leaves make it one of the most conspicuous settlers of its hardwood riparian forests and slope forests.

The Branched Bur-reed gets its name from its globular spiky ("Bur"-like) flowerheads which are arranged on a branching spike ("Branched"). It is a close relative of the larger plant Reed Mace; together, the two plants make up belts of reeds in shallow bodies of water in marshy habitats characterized by sedimentation.

The Burnt Orchid has the smallest flowers of all native orchis species. Its flowerhead blossoms from the bottom to the top. The flowers at the very top remain closed and are dark purple to blackish. Their "burnt" appearance is the likely origin of the scientific name: "ustulare" means "to scorch" in Latin. Both of their common names, Burnt Orchid and Dark-winged orchis, also refer to the hue of these blossoms.

The genus Utricularia is among those carnivorous plants which prey on small aquatic organisms to cover their nutrient needs. The Common Bladderwort may be occasionally found in certain backwaters of the Lobau.

Common Frogbit is a free-floating aquatic plant with long hanging roots. New plantlets form at the end of its long runners, often building huge floating colonies.

Common Hornwort – sometimes called Rigid Hornwort – is a free-floating, submerged aquatic plant which is most often found in backwaters.

In the Donau-Auen National Park, Common Nettle – also called Stinging Nettle – can grow in nearly impenetrable corridors taller than the average-sized person and makes up a large portion of the underbrush in the park. Together with swarms of mosquitoes, the Common Nettle encourages visitors to stay on the walking paths and thus ensures that large portions of the National Park remain pristine.

Reaching towering heights of up to 4m, Common Reed is the largest native grass species and it dominates reed vegetation in slow-moving to stagnant wetlands ponds and backwaters. Expansive reed sedimentation zones can be found in the Lower Lobau area of the Donau-Auen National Park.

The Cornelian Cherry is a deciduous species native to Central and Southern Europe which thrives best in the Donau-Auen National Park in dry areas at higher elevations. This species has long been popular thanks to the bright yellow flowers which appear early in the year, usually in March, and due to its edible and highly versatile fruit.

The Crack Willow is a medium-sized tree which is rare in the Donau-Auen National Park but found in the softwood riparian forests of the Danube wetlands and in damp meadows. It is called "crack" willow because its twigs break off easily at the base. Is more likely to occur as hybrid form with the White Willow. Thrives on deep soils with a good supply of moisture.

Cypress Spurge prefers dry and warm habitats. In the Donau-Auen National Park, the plant may be spotted along the Marchfeldschutzdamm (Marchfeld protective barrier). This dyke is an important refuge for meadow flora and fauna of the Marchfeld area.

The Dogwood is a deciduous, densely brachiate shrub which is easily identifiable, even in the winter, thanks to the red colour of its bark. It normally reaches a height of up to 4m. It is the most common type of shrub in the wetlands and can be found nearly everywhere. It propagates quickly by way of robust tillers.

The Early Spider Orchid, Late Spider Orchid and Bee Orchid have certain similarities. However, the Early Spider Orchid can be easily differentiated from all other orchid species by way of the markings at the centre of its lip, which are bluish to dark violet and often in the form of the letter "H".

European Birthwort prefers warmer, low-elevation climes. This plant is most remarkable for the way it is pollinated: small flies are "taken hostage" in its flowers and are not released until the stamen has been fully stripped. The flies, now heavy with pollen, are then released in order to pollinate neighbouring flowers.

The Field Elm may grow to heights of up to 35m. It normally has a regularly rounded crown and many branches. Its ideal ecological environment lies in the wetlands surrounding major rivers, where it – along with the English oak – constitutes the upper storey of damp and young hardwood riparian forests. Today, having been decimated by Dutch Elm disease in the last few decades, it has been included as one of the threatened tree species on the IUCN Red List. In the National Park, the Field Elm is most likely to be found in the hardwood riparian forests.

The Green-winged Orchid is a member of the Orchidaceae family. It blooms early in the year – from April to June. Its scientific name derives from the Greek "moros", which means fool, and refers to its flower, which looks a bit like a fool's cap. Another common name is Green-veined orchid due to the markings on its flower.

Hop is an ancient crop plant whose fruit is used to flavour beer. This liana uses its hairy, twisting stems to twine itself around other plants and scramble upwards. The tips of young shoots are considered a delicacy: they may either be eaten raw or cooked like asparagus.

One vernacular name for this early-bloomer is "pilewort", named thus because the small fleshy roots of this plant resemble the affliction (haemorrhoids) and the plant was traditionally used to alleviate the symptoms of the malady. One common German name ("Scharbockskraut") relates back to the use of the vitamin-C rich leaves of the Lesser Celandine to treat scurvy.

Lily-of-the-Valley is a toxic plant often found in thick colonies of Ramsons. When collecting Ramsons for consumption, great care must be taken not to mix up the two plants.

The Military Orchid gets its name from its flowers: the petals form a little helmet and the lower lip is lobed into what looks like little arms and legs, making the blossom resemble a solider with a helmet.

Mistletoe is a hemiparasitic evergreen plant which perches on the branches of deciduous trees, thus leeching water and mineral salts from these woody parts. Larger Mistletoe specimens can in fact kill off the branches of trees by dehydrating them in the extreme.

The Purple Willow is a pioneer shrub colonizing recently-formed gravel islands and river banks in the wetlands of the Alpine foothills. Characteristic are its thin, flexible stems which often display a reddish hue; these excellent materials are often harvested for binding. The shrub's intensive root structure makes it possible for it to penetrate deep into gravel and to fortify these locations.