364 safford: notes on dahlia 



The great fertility of the atomic theory has produced such a 

 mass of systematic knowledge that the province of atomics is 

 easily defined. Moreover, the definiteness and comparative 

 simplicity of atomic systems makes classification easy. This is 

 still more striking in the case of electronics, which perhaps may 

 be even more productive of systematic knowledge than atomics 

 has been. To some, attention to nomenclature is considered 

 trivial, but early in his career Faraday remarked the importance 

 of clever definitions which he always recorded, and demonstrated 

 by his example the close relation between the progress of science 

 and its nomenclature. Moreover, if the main purpose of science 

 is economy of thought, it is as necessary to systematize and 

 classify facts already known, as to discover new facts only to 

 have them buried unappreciated. 



BOTANY. — Notes on the genus Dahlia, with descriptions of two 

 new species from Guatemala. W. E. Safford, Bureau of 

 Plant Industry. 



The impression that the many "double-flowered" dahlias of 

 our gardens are forms created by modem horticulturalists from 

 single-flowered types is erroneous. In the earliest illustration 

 of plants belonging to this genus, made more than three cen- 

 turies and a half ago, only double-flowered forms are repre- 

 sented. Indeed, the genus itself was based by Cavanilles on 

 Dahlia pinnata, a plant with double heads identical in form with 

 certain "peony-flowered" dahlias of modern catalogues. Fran- 

 cisco Hernandez, the protomedico of Philip II, sent by his sover- 

 eign in 1570 to New Spain to study its resources, figured at 

 least three dahlias under the Aztec names Acocotli, Cocoxochitl, 

 and Acocoxochitl, all of which are derived from cocotli, signifying, 

 Hke the word "syringa," a hollow-stemmed plant; acocotli hter- 

 ally translated becoming "water-cane," or "water-pipe;" cocoxo- 

 chitl, "cane-flower" or "hollow-stem flower": and acocoxochitl, 

 "water-pipe-flower." It is interesting to note, in connec- 

 tion with this vernacular name, that it was also applied by the 

 Aztecs to plants of distinct families, including umbellifers, one 



