— igi — 



from the smallest thread-like roots which could be found ; the other 

 marked B, from !-touter roots from one-eight to one-fourth of an 

 inch in diameter. 



The length of the cuttings varied from one-sixteenth to one inch 

 in length. They were planted in'pots and placed in the cool house 

 April 12. The results of the experiment are in part indicated in 

 the following table : 



Experiment 

 Number. 



Size of 

 Cutting. 



I , 



6, 



7. 



9 

 lo. 



A 

 A 

 A 

 B 

 B 

 B 



Length of 



Cutting m 



Inches. 



_i 



X 



1 



1 6 



'A 



No. of Cut- 

 tings Sown. 



Number of 

 Plants. 



72 

 72 



24 



36 

 36 

 24 



o 

 o 



I 

 o 



5 



24 



As a general result of the experiments it may be inferred that 

 minute fragments of the roots of Canada thistle, when left in the 

 soil are not likely to grow, while very small portions of roots of a 

 somewhat larger size are pretty sure to produce new plants freel}'. 

 It should be noted, however, that the .soil in which the cuttings 

 were placed was almost constantly too damp — a condi.ion which 

 could not well be avoided for reasons not necessary to mention 

 here ; so that the inference may fairly be drawn that the results 

 above recorded do not show the full power of the Canada thistle 

 to multiply itself by root-propagation. 



ON THE VITALITY OF WEED SEEDS. 



During the season of 1879 a considerable collection of .seeds of 

 various weed plants were made for the Botanical Department, the 

 special purpo.se of which was to aid in naming such seeds or 

 plants as might be .sent for identification. As a part of a general 

 study during the past season of the physiology of weed plants, a 

 luimber of these .seeds were tested as to their vitalitj^ The col- 

 lection was kept in the Botanical Museum, the seeds being corked 

 up in small tx)ttles. The conditions were not favorable to the 

 preservation of the vitality of the .seeds, as the mu.seum was al- 

 most always hot and dry, especially in the winter, when constant- 

 ly steam heated. 



Thirty-two kinds of seeds, (or in the ca.se of the wild carrot, 



