In Iguazú National Park, the winds coming from the Atlantic cause rains of around 2000 annual millimeters evenly distributed, and the environment humidity is reinforced by the strong night dew, it is about 75% to 90%. These high temperatures and humidity conform a true green house with the best conditions for terrestrial life.
The "misionera" jungle embraces an extension of 27.000Km2 and it constitutes the extension of the Paraguayan Brazilian forest in Argentina. The abundant rains and the high temperatures contribute to its growing. It is a closed forest, compact, of perennial foliage, conforming true vegetable walls that can be crossed only with the help of axes and machetes. The main characteristic of a forest is the multiplicity of vegetation strata that occupies the whole space between the land and the height of the biggest trees. The missionary forest is distributed in several strata occupied by trees (superior stratum) bushes (middle stratum) and herbs (inferior stratum). The trees of more than 30 meters height belong to about 90 different species. Among the smaller trees there are bushes that grow below the trees, there isn't a dominant species. The soil is covered by a dense herbaceous vegetation. The lianas, epífitas, palms, arborescent ferns and bambues hinder even more the access making that the different strata are founded one to each other. Although three are different green tones, there aren't flowers of bright colors. The jungle is exploited due to its timber richness, and by its communications ways that facilitate the transport of big shipments through the rivers
The missionary flora includes arboreal species of great height, with trunks of about a meter diameter. They are very appreciated for the timber industry by the wood quality. Among the standing out ones are:
- Guatambú: It can overcome the 30 meters. Its wood is hard, white and heavy.
- Laurel Negro: Its wood has a very strong scent that limits its use in carpentry.
- Peteribí: It is very appreciated by its use in fine carpentry, its wood is light green brownish, lightly marbled.
- Cedro Misionero: It has a high quality wood, it has almost disappeared of the missionary forest. It was object of intensive exploitation because its wood is rosy, fragrant, veined and easy to work.
- Pino Paraná o Pino de Misiones: It is a high tree of up to 50 meters height, with rosy-brown bark and which foliage is only in the trunk's apex, in the form of an open parasol. It can live several centuries.
- Alecrín: Its leaves are perennial and it has flying roots, its trunk has reinforcements or ribs in its base that are articulated with their roots.
- Timbó o Pacará: It is also called "oreja de Negro" due to its fruit shape, it has up to 30 meters height and its trunk can reach 1,60 meters thickness. When it grows in the open spaces it ramifies to short height in thick divergent branches, showing similar aspect to a gigantic "acacia" with umbrella shape. Its flowers are white or red.
- Viraró: Its wood is very coveted by the forest industry.
- Lapacho Negro: Because of its height or diameter it is one of the jungle's giants. Its trunk can measure 1,5 meters diameter and 30 meters height. When winter comes to an end, before giving leaves, it is covered of pink flowers that attract thousands of humming birds.
- Pindó: It is a palm tree which trunk is very thin and it has about 20 meters height, it is crowned by a group of long pinnadas leaves.
There are other species that have another type of applications, among them we can mention:
- Incense: Its bark has an aromatic substance similar to the myrrh that the Jesuit used in the temples instead of true incense. It is a big dimension tree, with long shaft, its wood is hard, fragrant, smoothly veined of great duration and resistance.
- María Molle or Carne de Vaca: it contains aromatic resins.
- Espina de Corona: It contains in its fruits a gum used in cosmetics, chemistry and goodies.
- Ibapoí or guapoy: It is also called "higuera brava" (brave fig), crazy fig or agarrapalo, because its seeds germinate in other trees cracks, from where it throws its roots to the soil and progressively it strangles and suffocated its support, developing its own branches on the former trunk.
In the intermediate stratum the arborescent ferns are standing out ones. Among them we can mention the chachí that grows in the thicket because the sun rays are harmful for it. It has a height of about 4 to 5 meters with great leaves of up to 2 meters length, it constitutes a vegetal relic, because it reminds the big ferns that constituted the arboreal dominant vegetation during the carboniferous period and that were extinguished about 250 million years ago. Its use for interior decoration as orchids' support, has put the species in serious risk. In this stratum we can find the mate herb (yerba mate) which leaves, dried and milled are used to prepare a very popular south American infusion.
Under this stratum there is another one in an atmosphere of dimness, it is formed by a lot of ferns and bushes. Among them we can mention the "Ortiga Brava" (Brave nettle), which has got very big leaves and it is very stingy.
The thicket is dominated in parts by bambúes and reedbeds that form impenetrable walls from 10 to 15 meters height. He most standing out ones are: the thin Tacuarembó which solid cane has 1,5 centimeters diameter, the fragile tacuapí , the thorny yatevó and the giant Tacuaruzú which offers hundreds of erect canes, curved in its ends, that may reach up to 30 meters height. It flourishes only once in its life, the flowers appear after 25 or 30 years, making simultaneously all the tacuaras and then they come to an end after fructification. Its seeds germinate quickly and in a few months the forest is repopulated.
The herbaceous stratum constitutes the inferior level covering the soil, there are plenty of gramineous of wide leaves, ferns and non woody grasses. Among them the begonias are the standing out ones. They are very well known as interior ornamental plants. On the soil abundant organic matter in decomposition is accumulated; giving place to the growing of fungus, mosses and lichens .
As the light and the rain are monopolized by the superior strata, several plants appeal to varied strategies to reach them. The lianas , are the climbers per excellence, they entangle or are hooked to the trees, they get the superior branches, they hang like ropes, forming a vegetable tangle. They have leaves and flowers to any height, they have beautiful colors and many species have been adopted by the horticulture with ornamental ends.
One of the most notorious characteristics of the forest is the epífitas proliferation, they are plants that have sacrified all contact with the land and its nutrients in pro of a place to the sun in the big trees cones. They use other species as support, they are not parasites. They absorb the air humidity by means of air roots. Among the main species are the bromeliáceas, they include the pineapple and many ornamental ones which roots are used to grab to trunks and branches, they have long and narrow leaves grooved to make the rain water flows towards its center. These height ponds have an own fauna since they are exclusive habitat of some spineless ones such as mosquitoes, there are also frogs which tadpoles grow protected from the aquatic predators. To this family belong the "Claveles del aire" (carnations) and the Caguatás which have yellow, pink and reddish flowers. Its leaves are frequently taken by the Cai monkeys that eat its tender parts.
From the epífitas species we can especially mention the orchids: They capture the atmosphere's humidity with their air roots that are wrapped in an spongy fabric of dead cells to protect them from drying. They are thicker on the leaves base to store nutritions and humidity. All the orchids have exotic shapes to guarantee the pollination. The inferior petal is more developed, and it serves as landing platform to the insects that are attracted by their strong fragrances. Its only one stamen discharges a compact pollen mass on the head and back of the insect that goes there to suck the nectar and that later on will transport the pollen. Each orchid produces a lot of small seeds that are easily disseminated by the breeze. The new plant not only depends on germination but to grow it must associate to a kind of specific fungus for each orchid species with which it will have a symbiotic relation. The fungus will enjoy the synthesized sugar produced by the orchid and this last one will use the fungus proteins. The missionary forest is full of orchids, they are: Sophoronitis coccinea that gives bright orange flowers, the Miltonia flavescens that has lots of yellow flowers in spring, the Campylocentrum, it doesn't have leaves, the Brassavola perrini, it has big white flowers, the Flor de Patito of the Oncidium gender, it has yellow flowers with brown spots, and many others that contribute to the beauty of trees that give them home.
The orchids, of high ornamental value, suffer the pillagings of collectors, to such an extent that many of them are in danger of extinction, requiring special protection measures as the creation of natural reservations. Another prominent epífita is the Guembé, it is an arácea of big conaceous leaves of about 80 centimeters length, with long roots, hanging to nurture the plant. When the roots reach the soil, they penetrate into it to provide the plant of nutritious - in this case they are climbers. It also grows in the land having a thick and short trunk. When the guembé seeds are deposited through the animals' excrements in cracks or cavities of the trees, they take advantage of the humidity and of the organic matter becoming a big epífita using to its guest like support.
Capuera: Where the fire or the man's hand have destroyed the forest, it grows a vegetation of grasses, bushes and trees that quickly form a secondary community to which shade the umbrófilas species grow. The most important species are: Fumo Bravo, it is a tree that reaches up to 5 meters in 2 years. Its berries like the ones from other species like the Palo Polvora, Mandioca Brava, Talas Trepadoras and Casearia Sylvestris, attract a lot of birds and mammals that feed of them. Another typical species from the Capuera is the Sangre de Drago, which latex is used in Medicine and which foliage with green, gray, orange and reddish leaves made of it an ornamental plant. The Ambay is a moracea of erect stem that ramifies to great height forming a parasol cone with big green leaves, in its superior face and a white face in its setback. It has a hollow trunk, that is divided by traverse partitions. It is inhabited by ants of the Aztec gender: they are small reddish and very aggressive.