(Universidad Central del ecuador, 1958-07) Naranjo Vargas, Plutarco
In the tropical countries of Central and South America there grow only a few species of plants that produce allergenic pollen, and these are not widely distributed, with the exception of the grasses which otherwise have a feeble sensitizing power. The output of pollens from grasses is very limited in the high mountains because of the lack of flowering of such plants. The most important species correspond to the families Amaranthaceae, Chenopodiaceae, and Compositae.
