The Manual on Uniform Traffic Control Devices (MUTCD) is approved by the Federal Highway Administrator. as the National Standard in accordance with Title 23 U.S. Code, Sections 109(d), 114(a), 217, 315, and 402(a), 23 CFR 655, and 49 CFR 1.48(b)(8), 1.48(b)(33), and 1.48(c)(2).
The dominant vegetation types are grassy prairie and grass steppe in which numerous species of the grass genus Stipa are particularly conspicuous. Pampas grass (Cortaderia selloana) is an iconic species of the Pampas. Vegetation typically includes perennial grasses and herbs.
Subtropical plants dominate the Gran Chaco in the north, with the Dalbergia genus of trees well represented by Brazilian rosewood and the quebracho tree; also predominant are white and black algarrobo trees (prosopis alba and prosopis nigra). Savannah-like areas exist in the drier regions nearer the Andes.