56 White. 



domesticated races than in wild forms. This statement is based on the 

 following facts: First, cnltivated plants are much more accessible to 

 observation than those in nature, and secondly, when the hereditary 

 form of this variation occurs, it is more likely to be perpetuated, both 

 as a homozygote and heterozygote, than were it subject to natural 

 selection. In view of these facts, the more frequent appearance of the 

 anomaly in cultivated plants may be erroneously credited to repeated 

 origin, when it is only a case of hereditary transmission (see 

 Emerson 1912b). 



Among field crops such as sugar beets, corn, peas, sweet potatoes 

 and pine -apples, fasciations are often extremely numerous. These 

 anomalous individuals are commonly found growing beside the normal 

 plants in the same field and under apparently the same environment. 

 Blodgett (1905) reports a case of a field of peas (Pisum sativum) 

 where not over 10 per cent of the vines were unfasciated. Conard 

 (1901) finds the sweet potato so commonly fasciated in all parts of the 

 United-States where it is an important crop, that he concludes it to be 

 a hereditary phenomenon. M. T. Cook (1906) mentions a variety of 

 pine-apple ("Smooth cayenne") which gives over 25 per cent abnormal 

 fruits of a fasciated nature. Other pine-apple varieties such as „Puerto 

 Hico" also produce fasciated fruits, but not in large numbers. Sugar 

 beet plantations and cornfields both yield a plentiful supply of fasciated 

 material, the former of the stem, the latter of the female inflorescence 

 (ear). I doubt if there is any corn-grower who has not observed these 

 occasional flattened ears in his field. East, Hayes and Emerson 

 have each isolated pure strains of such plants. Recently I have observed 

 fifty or sixty extremely fine examples of fasciation among a couple of 

 hundred hybrid Bosa Wichuraiana plants planted along a Boston parkway. 

 Other species of cultivated plants in which the anomaly is common are 

 Lilium speciosum album corymhiflorum, Evonymus japonica, Riihus sp., 

 Tetragona expansa, Helianthus annuus, Cucurbita melo (all de Vries); 

 Cotoneaster macrophylla (Worsdell, 1905); Prunus sp. (Maiden, 1913, 

 White, 1912). 



C. Classification. 



Variation may be viewed from two angles; the strictly morpho- 

 logical, which takes into consideration external form, color, anatomical 

 structure, and other physical features, or the physiological, which 



