The pampas, which cover so large a part of the republic, have no native trees whatever, and no woods except the scrubby growth of the delta islands of the Parana., and a fringe of low thorn-bushes along the Atlantic coast south to Mar Chiquita and south of the Tandil sierra, which, strictly speaking, does not belong to this region.
The provinces of Santa Fe, Cordoba and Santiago del Estero are only partially wooded; large areas of plains are intermingled with scrubby forests of algarrobo (Prosopis), quebracho-blanco (Aspido-sperma quebracho), tala (Celtis tala, Sellowiana, acuminata), acacias and other genera.
The surface of the plateau is generally open campo and scrubby arboreal growth called caatingas, but the streams are generally bordered with forest, especially in the deeper valleys.
The plateau, known as the Ogaden plateau, everywhere presents the same monotonous aspect of a boundless steppe clothed with a scanty vegetation of scrubby plants and herbaceous growths.
In the canyons of the Edwards Plateau grow the pecan, live oak, sycamore, elm, walnut and cypress; on the hilly dissected borders of the same plateau are cedars, dwarf and scrubby oak, and higher up are occasional patches of stunted oak, called "shinneries."
The vegetation consists almost entirely of scrubby bushes of several varieties, including tamarisks and wild briers, of reeds (kamish), and of grass on the yaylaks (pasture-grounds) of the middle ranges.
There is but little natural vegetation to be seen - ragged yucca trees, many species of agave and cactus, scrubby mesquite bushes, sage bushes and occasional clumps of coarse grasses.
On the upper verge of the pine forests, or in the scrubby vegetation just beyond, the following are not uncommon - black woodpecker (Picus martius), ring-ousel (Turdus torquatus), Bonelli's warbler (Phylloscopus Bonellii), crested tit (Parus cristatus), citril finch (Citrinella alpina), siskin (Chrysomitris spinus), crossbill (Loxia curvirostra), nutcracker (Nucifraga caryocatactes), blackcock (Tetrao tetrix), and the alpine varieties of the marsh-tit (Parus palustris, borealis) and tree-creeper (Certhia familiaris, costae).
These upland forests are of a scrubby character and are called catingas.