Marshes - and especially fresh-water marshes - are peopled by a number of plant species having underwater roots and sometimes even underwater - or just emerging - leaves. These plants are called hydrophytes, that is, "water plants". Among them, the Frogbit, the Willow grass, several types of Long-stalked Pondweed and Buttercups, the White Water-Lily.
Other species, called helophytes, have underwater roots but emerging stems and leaves. Among them, some common species such as the Common reed and the Broadleaf Cattail, but also some localised ones, such as the Lesser Water-plantain, the Branched Bur-reed and the Arrowhead.

These plants live on the edge of wetlands and wet meadows, since they need to be flooded for some time but can not live with their roots underwater all the year round.
The most common species, such as the Purple Loosestrife, the Marshmallow, the Comfrey and the Hemp agrimony, can be found even along countryside ditches. Some other species live only on the edge of marshlands and the main canals, such as the Flowering Rush and the Yellow Iris. The Park also houses some rare and localised species, such as the Euphorbia palustris and the wonderful Summer Snowflake, which can be found especially in Punte Alberete.

The Park's several woods are characterised by distinguishing features depending mainly on the degree of humidity and soil type. Besides considering the dominant tree-type, woods are characterised by the herbaceous species inhabiting their thin undergrowths and glades.
The wettest glades are peopled by Birthworts and Bugles, whereas the pinewoods' dry and sandy soils house the White Rockrose and the Viper's bugloss; more common species, such as the Daisy, live in intermediate situations, as well as the Rampion and Brushgrass.

With their tangled stems and their roots under the mud, the shrubs living in the Park's marshlands, which are often flooded, remind of mangroves.
The dominant species is the Goat Willow, which lives in fresh-water lagoons and represents the transitional step between reed beds and dry areas. Next to it, Alder buckthorns, Guelder Roses and Purple Willows people the wettest areas, but it is also possible to find Buckthorns, Dogwoods, Wild Pears and Dyer's greenweeds. These two last species can stand the presence of salt and therefore live also next to brackish lagoons.

The undergrowth and the woods edges are protected by thick - and often thorny - shrubs. Besides representing a very important habitat for many animal species, they protect the wood and contribute to the preservation of its microclimate, i.e. of its temperature and humidity. Most of these plants are mesophytes, with beautiful flowers and shining berries, living also along roads and in field fences: Hawthorns, Blackthorns, Common Privets, Dog Roses, Barberries, Spindles. Arid woods are peopled by less common species, such as Rosa sempervirens, Butcher's-broom and Scorpion senna.

Psammophilous plants, that is to say plants loving and living on sands and dunes, present typical adaptations: they have tough leaves to resist the abrasive action of wind-driven sand, leaf-like hair to protect themselves against evaporation in summer, long roots and fleshy leaves to hold water.
The sandy areas lying closer to water are peopled by Sea Rockets, while mobile dunes are peopled by Saltworts and Sea Bindweeds, and firm dunes by Cyperus kalli, Sea Medick and Sea Holly.

Spontaneous plants are protected on the whole Park territory. They cannot be picked up or damaged in any of the Park natural environments, be it lagoon, marsh, pinewood or dune. As an exception to these regulations, some undergrowth products can be picked up according to specific norms. However, 41 species are specially protected by the regional law 2/77, art. 4; among these, Grey Cistus, Marsh helleborine, Summer Snowflake, White Water-lily, Italian buckthorn, several Limonium and Orchid species.
Two species, Saltwort and Kosteletzkia pentacarpos, are also protected by the European Directive 92/43/EEC, annex II.

Far from living only in equatorial rain forests, several species of Orchids represent the most beautiful flowers of the Park's spontaneous flora.
With 32 protected species, Orchids are the park's most protected family by the regional law 2/77.
The most important among them are those linked to marsh and wet environments: Marsh helleborines, Marsh orchis and Orchys palustris. Some other species live in the woods, such as Narrow-Leaved Helleborines and Man orchids, or in the Park meadows and banks, such as Toothed Orchids, Green-Winged Orchids and Bee orchids.