The eastern slopes of the Patagonian cordillera are cloaked, for most of their length, in forests dominated by the various species of Nothofagus southern beech . Two species run the length of the forests, from the northernmost forests of Neuquén to Tierra del Fuego: the lenga (upland beech); and the ñire (lowland or antarctic beech). Both deciduous, they frequently grow in close proximity, so telling them apart can be problematic at first. At lower altitudes, the lenga is by far the taller species, but closer to the tree line, the two intermingle as dwarf shrubs in impenetrably dense thickets. The lenga , capable of flourishing on incredibly thin topsoils, tends to form the tree line, reaching up to 1600m above sea level at the latitude of Neuquén. The ñire , which rarely grows more than 15m tall, tends to be found close to water; and whereas in autumn both species turn a remarkable variety of hues, it is the ñire that has the most vibrant palette, with astonishing garnets, golden yellows, rusty oranges, and pinks the colour of rosehip jelly. By comparing the leaves of the two species, you can always verify any preliminary identification: lenga leaves have lots of veins, with each band between the veins having a uniform double lobe on the edge; ñire leaves have far fewer veins, and each band has a less regular, crinkle-cut edge with several lobes. Associated with lenga and ñire are three intriguing plant species: false mistletoe ( farolito chino ), a semi-parasitic plant that draws sap from its host as well as producing its own through photosynthesis; verdigris-coloured lichen beards ( barba del indio or toalla del indio ), which need unpolluted air to flourish; and the llao llao tree fungus, also called pan de indio ("Indian's bread"). When young, it does have a faintly sweet flavour, but is low on nutritional value. The llao llao produces the characteristic brain-like knots on trunks and branches that are so beloved of local artisans, who use them to craft animals and ashtrays. Lenga and ñire are the only species that occur at all latitudes where you can find Patagonian Andean forest. The next most prominent tree species are two related evergreen beeches, the more northerly coihue and the guindo (or coihue de Magallanes ), found mainly in Tierra del Fuego. Both have fairly smooth bark and distinctive laurel-green leaves that are small, shiny and tough, with a rounded shape and tiny serrations on the edge. Both trees grow only in damp zones near lakes or, in the case of Tierra del Fuego, by the shores of the Beagle Channel, where they reach 25-30m in height. In central Neuquén, you find one of Argentina's most remarkable trees, the araucaria monkey puzzle , which grows on poor volcanic soils, in widely spaced pure forests or, more normally, mixed with species of Nothofagus. The forests of Parque Nacional Lanín contain two species of broad-leafed Nothofagus not found anywhere else: the roble pellín (named for its oak-like leaves), and the raulí (with more oval-shaped leaves), which together often form mixed, low-altitude woodlands. Also confined to the area is the radal , a shrubby tree with a creamy whitish flower and a greyish wood that is valued by craftsmen for its beautiful speckled vein, reminiscent of a sloughed snakeskin. The most diverse type of forest in the region is the rare Valdivian temperate rainforest ( selva Valdiviana ), found in patches of the central Patagonian Andes from Lanín to Los Alerces, usually pressed up against the Chilean border around low passes where rainfall is at its heaviest. This verdant tangle requires extremely high precipitation (3000-4000mm annually) to flourish, and it is marked out from the rest of the forest by several distinguishing factors: different layers of canopy, thick roots breaking the surface of the soil, and both epiphytes and llianas. Two other tree species found only in the central Patagonian lake district are the scarce arrayán myrtle, always found next to water, and with a glorious, flaky, cinnamon-coloured bark; and the mighty alerce , or Patagonian cypress, which resembles a Californian redwood and is one of the world's oldest and grandest tree species. The understorey of the forests is dominated in most places by dense thickets, up to six metres high, of a bamboo-like plant, caña colihue , a mixed Spanish and Mapudungun term that means "tree of the place of water". Every 7-12 years they flower, die and reproduce - a phenomenon that can spark a lemming-like plague of colilargo mice. The most stunning shrub, if you catch it in bloom (late spring or autumn), is the notro firebush (or ciruelillo ), whose fiery flowers resemble miniature scarlet crowns. Another native to these parts, the fuchsia , has conquered the world as a garden favourite. Growing in Tierra del Fuego, and looking rather like a glossy rhododendron, the evergreen canelo takes its Spanish name from the fleeting cinnamon taste of its bark, a taste rapidly followed by a peppery tang. In English it is known as Winter's bark, after a certain Captain Winter of Francis Drake's expedition, who discovered that its leaves helped to treat and prevent scurvy. The native wild holly ( muérdago silvestre ) has glossy, dark-green leaves and, in spring, clusters of yellow-orange fairy-bell blooms the size of blackcurrants. Of forest flowers, some of the most brightly coloured are the amancay , a type of golden-orange lily that carpets glades in central Patagonia in midsummer; and the brilliant yellow flowers of the yellow lady's slipper ( zapatilla de la Virgen ), whose snapdragon blooms bob on their delicate stems in spring. Lupins ( lupinos ), introduced by the British to enliven estancia gardens, have spread like wildfire through parks like Lanín, and, though considered a plague, they do put on a glorious show from late December to January, when in bloom. As you move away from the mountains towards the drier steppe, you'll often find a zone of transitional woodland , although the change from steppe to forest can be quite abrupt. In northern and central Patagonia, the woodland is normally composed of species like the mountain cypress ( ciprés de la cordillera ), or the autochthonous retamo , which flowers with pale-violet blooms. Found on mountain-valley floors or just above the tree line are peaty sphagnum moors ( turbales ) and bogs ( mallines ). Here you'll find chaura prickly heath, and you can munch away on its waxy, pinky-red berries, which have a spongy texture and look like miniature Edam cheeses. The creeping diddle dee ( murtilla ) is a common upland plant; there are several types of berries that go under the local Spanish name of mutilla . On rocky soils, look out for the common blue perezia ( perezia azul ) whose diminutive, mauve flowers have a double rosette of elegant, spatula-shaped petals.