66 



The Plant World. 



contrary to the generally accepted opinion that the plant is art 

 annual, and it was in view of this that the present writer an- 

 nounced his observations made in Mexico. It further appears 

 from the bulletin in question that in 1868 Kuhn announced that 

 the dodder lives over winter in the clover fields in Germany. 

 Later Sorauer stated that dodder is perennial, though Kerner 

 and Oliver take the opposite view, excepting with regard to 

 tropical species. Quite recently Hillman has held it to be an 

 unsettled question, and in view of the pertinacity with which 

 the view that the dodder is an annual is held, as observed by 

 Kuhn, it is not superfluous to draw attention once again to the 

 observations of Stewart, et al, and of myself. Stewart, et al, 

 particularly, offer in the bulletin referred to a mass of pertinent 

 evidence, which is of especial importance because of the economic 

 bearing of the question. 



Alabama Polytechnic Institute. 



A REPEATED CYCLE IN ASSIMILATION. 



By B. E. Livingston. 



In the Rothamstead Experiment Station, at Harpenden, 

 near London, my attention was called by Professor Hall to a 

 plant of Asplenium nigrum which is of exceptional physiological 

 interest. In the year 1874 a certain soil sample, of something 

 over a liter volume, was placed in a large-mouthed bottle and 

 hermetically sealed with cork stopper, sheet lead capsule and 

 sealing wax. The containing bottle has a capacity of perhaps 

 two and one-half liters, so that there is above the soil a roomy, 

 moist chamber, for samples at that time were preserved without 

 drying, in the condition in which they were obtained from the 

 field. 



In this soil sample developed the fern plant here referred 

 to. The room in which the soil samples are shelved is sufficiently 

 light so that the fern has grown to fill the space allotted to it, 

 having now a large mass of mature leaves, below which are 

 withered and decaying ones and above which many young 

 leaves are unfolding. Just how old the plant is it is, of course, 

 impossible to state, but there is no reason to believe that it did 

 not spring from the thallus within a year or two of the time the 



