of the species. (9, 12, 13, 81, 36, 118, 115, 146, 177a, 
200, 206, 207, 214, 216*, 217*, 220) 
Dahlia coccinea Cav. (D. rosea Cav.); D. pinnata 
‘av. (D. variabilis Desf.); D. Lehmannii Hieron. (D. 
Mawonii Saff.): Acocowdchitl, acocoth, dahlia. 
That dahlias had long been cultivated before their dis- 
covery by Europeans is indicated by the great degree of 
variability which these plants showed when first intro- 
duced into Europe, and by the great variety observed by 
Hernindez (98, 173, 188). The tuberous roots of the 
dahlias are edible, and Camp (84) believes that they were 
first cultivated as food plants. The huge ‘‘tree’’ dahlias, 
D. Lehmannii (D. Maxonii) and perhaps D. excelsa 
Benth., are much cultivated in southern Mexico and 
Guatemala, where they serve as living fences. There is 
no comprehensive study of these plants available, and 
their relationships are but poorly understood. It is al- 
most certain that hybridization has played a considerable 
part in the origin of the cultivated forms, some of which 
are polyploids. (84, 62, 178*, 183*, 184) 
Diospyros Ebenaster Retz.: Tli/zapotl, zapote 
prieto, black sapote. 
Though a popular fruit in parts of Mexico, the black 
sapote is found unattractive by some because of its dark 
colored pulp. It is related to the better known persim- 
mon and produces a fruit of good size. Some have 
thought it a native of the East Indies, but the evidence 
seems to indicate a Mexican origin (138). There is no 
recent study of this genus. (31, 95, 133, 188, 158*, 164%, 
191, 199) 
Gossypium hirsutum L.: [zcat/, algodén, cotton. 
Cotton was an important fiber plant in much of Amer- 
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