Studies of Teratological Phenomena. 63 



would explain the manner in which the peculiar anatomical features 

 could be produced through the fusion of several normal stems. 



Knox (1908) from an investigation of the anatomical features of 

 fasciated Oenotheras also concludes in favor of Moquin-Tandon's 

 deduction. She finds no evidence of fusion of stems in the growing 

 region and calls attention to tho fact that ring fasciations may break 

 on the side and develop the linear type. According to this author all 

 types are the result of the enlargement of a single growing point. 



Church (1905) and Worsdell (1905) favor a very modified form 

 of the concrescence theory of Linne. Worsdell believes fasciation to 

 be the result of a compromise between two inherent ancestral tendencies, 

 and rarely a case of real mechanical fusion in the Linnean sense. Two 

 opposed forces are operating in the organism, — one inducing integrity, 

 the other producing plurality of parts. Fasciation in higher plants is 

 a reversion to the ancestral branching character of the lower plants, 

 such as lycopods, ferns and algae. In other words, this anomalous 

 character in a morphological sense is a case of the congenital fusion 

 of an unusual number of branches. The reason advanced to account 

 for the fusion in one plane is the ancestral or primitive branching 

 character, — algae, ferns, etc. being said to branch primarily in a 

 single direction^). In this sense, Worsdell's hypothesis of congenital 

 fusion and increase in number of parts is a modification of the "con- 

 crescence" theory. 



The morphological aspect is mainly descriptive and gives but little 

 insight into the real or perhaps more fundamental nature of fasciation. 

 On the other hand, physiological investigation, though increasing the 

 complexity of the prol)lems involved in a study of fasciation, gives at 

 least deeper descriptive knowledge of its nature and the causes which 

 produce it. 



2. Physiological. 



a) General considerations. 



Variations of any kind, from the standpoint of physiology, may 

 be placed for all practical purposes into two main categories, those 

 inherited (germinal) and those uninherited (somatic). This statement 



^) Braun as far back as 1859, advanced a somewhat similar view (see Roy. Soc. 

 Publ., London). 



