The forests of Lann National Park and Reserve are very valuable for ecologists because they are the only forests of araucaria (monkey-puzzle tree) among the naturally protected areas. The same is true of the woods of roble pelln and raul. Together with these arboreal species, Lann Park includes a variety of herbaceous species and bushy plants that are only to be found in northwestern Neuqun, not having been seen up to the moment in any other protected area of the country.

Species of restricted distribution, considered "of special value":

Bushes and herbs:
Acaena leptacantha, Adesmia papposa, Aster peteoranus, Azorella incisa, Baccharis benzanilleana, Calampelis scabra, Carex minutissima,Centipeda elatinoides, Chaetantera elegans, Chenopodium philippianum, Dioscorea brachybotrya, Eryngium pseudojunceum, Haplopappus marginalis, Libertia chilensis, Lomatia dentada, Mulinum albovaginatum, Osmorhiza glabrata, Paspalum dasypleurum, Poa andina, Poa Hachadoensis, Ribes valdivianum, Senecio comberi, Senecio jobii, Silene cuspidata.

Exotic plants (introduced by man)
Pine forestry species, musk rose, poplars, lupines, etc.

Native (of local origin) plants:
Trees:
The predominant species are part of a prolific family of the genus Nothofagus, as well as 3 coniferous species:

Raul: Nothofagus procera (= N. Nervosa)
A large tree, reaching a height of 40 m. Its leaves, the largest in the genus (up to 9 cm length), have serrated edges and clear veining, changing color in fall.
This species is exclusive to Lann National Park and NOT to Nahuel Huapi National Park, and it lives together with roble pelln and coihue. Its wood is ideal for the manufacture of the best quality furniture.

Coihue: Nothofagus dombeyi
This is a nice looking evergreen attaining a height of 45 m. Its name in Mapuche language means "watery place". It has perennial, small, serrated bright green leaves. Its branches are arranged in horizontal planes, giving the impression of stratification. It usually displays galls on its branches and trunks, as a product of the action of the llao-llao fungus. Its wood is used for the building of bridges, docks and piles.

ire: Nothofagus antarctica
This is a deciduous dwarf tree or bush that reaches 15 m tall. It is a very adaptable colonizing species. It ramifies from the base into several main trunks. Its leaves are wavy, roundish and finely serrated. In fall it takes on a red hue. It is used for firewood and fence posts.

Roble Pelln: Nothofagus oblique
This is a deciduous tree that can reach 30 or 40 m. It has alternately placed lance-shaped leaves with serrated edges. Its non-decaying wood is used to constsruct docks, bridges and houses. This tree is the "wise tree" in the woods, according to Mapuche tradition. It is another species exclusive to Lann National Park.

Lenga: Nothofagus pumilio
This is a tall, straight-trunked tree, that gets stocky at the higher borders of the forests. It has rounded leaves that show regular notches every two veins. Turning a bright red color, it prettifies the appearance of the woods. Its wood is used by Mapuche artisans, for handcrafts and carpentry work.

Conifers:
Pehun: Araucaria araucaria
This endemic (exclusive) species is one of the most nice-looking trees in the park, attaining a height of 40 m. The fully-grown tree develops an umbrella-shaped crown. It grows on rocky soil and forms single-species forests. Its extremely hard leaves are evergreen. There are male trees with pollen-producing cones, and female ones with spherical cones, whose seeds, known as piones, are rich in carbohydrates and protein, being the staple food for Mapuche communities.

Cypress: Austrocedrus chilensis
A pioneer species in the wood, it bears winged seeds that prosper in rocky, arid soil. It has a very conical-shaped crown and short twigs with perennial scale-shaped leaves. It grows to 20 m height.

Maniu: Saxegothea conspicua
This tree with a pyramidal crown is commonly found in humid places. Its red bark shards off. Its simple straight dark-green leaves have two whitish stripes on the back. The male flower is a short ament (cone), and the female is a globe-shaped cone.