214 The Plant World. 



Some alterations such as that of Passiflora on Euonymous are 

 distinctly discontinuous, but in this particular instance it can- 

 not be shown that any permanent results would follow the oc- 

 currence of the dependent relation. Some features, however, 

 such as the development of haustoria, on roots and stems, would 

 be a distinct mutation, and is well illustrated by Kraneria,and 

 supposedly also by Cuscuta. The taking on of absorptive 

 functions by the epidermal cells of xeno-parasites as described 

 in the present paper, is to be recognized as a distinct nutatory 

 alteration. 



A direct and immediate atrophy of the various organs of the 

 shoot ensues as a result of the assumption of the parasitic rela- 

 tion, but the extreme stages of such reduction appear to have been 

 reached by gradual changes although it is evident that such a con- 

 clusion is almost wholly inferential. The transition from 

 autophytism to complete parasitism with attendant habital 

 characters, appears to have been gradual, since species may be 

 cited to illustrate all degrees of the alteration, but, on the other 

 hand, it is not impossible that the complete change may have 

 been made at once in some forms. Nothing in the entire matter 

 suggests progression or retrogression of all of the involved char- 

 acters by one method alone. 



Placing a plant in a dependent nutritive relation affects the 

 organs concerned in nutrition and transpiration, and the changes 

 which ensue may be connected more or less directly with ob- 

 vious causes. In addition, however, modifications resulting 

 from correlations are to be seen, while still other phenomena are 

 to be noted which are wholly incidental and may not be con- 

 nected in any purposeful manner with the existence of the plant. 

 It is indeed quite to be expected when a plant which has lived 

 thousands of years as an independent organism, is suddenly 

 placed under dependent conditions with respect to another 

 organism that it should display useless and aberrant qualities 

 and structures, some of which may be of a very striking 

 character. 



