Their surface, at first smooth, later becomes lumpy and tuberous from internal degeneration.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
There is a beautiful essay on old-fashioned flowers-those which are being ousted out of our modern gardens by such flowers as tuberous-rooted begonias, with their red combs always crowing like so many cocks; and one on chrysanthemums, a symbol of the onward march of culture.
"Life and Writings of Maurice Maeterlinck"
Jethro Bithell
He recommends that the inert tuberous layer of the bark be removed; prepared thus and powdered it is emetic in doses of 2.50-3 grams.
"The Medicinal Plants of the Philippines"
T. H. Pardo de Tavera