BUREAU OF PLANT INDUSTRY. 297 



rose oferanium has been somewhat interfered with by frosts, and a 

 possible deterrent factor has been developed, but it is believed that 

 we can work out ways of meeting these conditions except at times of 

 unusual severity. Among the weeds yielding interesting products 

 may be mentioned the ordinary fireweed, LeptiJon canadense {EHg- 

 eron canadensis). This plant occurs in large quantities over a wide 

 area and contains an oil yielding a number of products valuable in 

 the arts. 



Hop investigations. — The hop-improvement work has been con- 

 tinued by Dr. "W. W. Stockberger, Physiologist, with very interesting 

 results. Seedlings marked by great vigor and other desirable quali- 

 ties seem to have been obtained. The answer to the important ques- 

 tion of yield has not yet had time to develop. An intensive study of 

 a representative acre of hops with reference to sources of loss has 

 shown that practical parts of field handling are often neglected. The 

 number of vines trained is apparently a more important factor than 

 has been recognized. Further studies on field methods promise im- 

 portant results. In cooperation with Mr. Rabak, Doctor Stockberger 

 has been investigating the relation of certain hop constituents to the 

 quality and price of the products. The volatile oils have given very 

 interesting results. A study of the resins promises to be even more 

 significant. 



Tea-culti're IN^^:sTIGATI0NS. — The tea work at Summerville, S. C, 

 in cooperation with Dr. Charles U. Shepard, has been continued with 

 good results. A very satisfactory crop of tea was grown, harvested, 

 and promptly sold. The demand for American tea, especially in the 

 South, has increased to a great degree, and the question of a sale seems 

 to have been decidedly relieved. The efforts of Mr. G. F. Mitchell, 

 Scientific Assistant, to devise a practical pruner seem at last to have 

 been rewarded. Tea can now be pruned by machinery much more 

 rapidly and economically than heretofore, and summer pruning, not 

 always possible with h:ind labor, can now be resorted to with greater 

 freedom, with a resulting increase of yield. A closer system of pick- 

 ing has been followed during the past year, with the result that a tea 

 of very high quality has been obtained, at the cost, to a certain extent, 

 of quantity. 



POISONOUS-PLANT INVESTIGATIONS. 



The field and laboratory work on poisonous plants has been con- 

 tinued along the same general lines as heretofore, and has made good 

 progress. 



IjOCO-weed INVESTIGATIONS. — A study of the relation of the loco- 

 weed disease to the presence of barium in the weeds has been con- 

 tinued by Dr. C. D. Marsh, Physiologist, and his assistants, with the 

 conclusion that no connection can be shown to exist. The symptoms 

 of barium poisoning appear not to agree with those of the loco-weed 

 disease. A laboratorv studv of the constituents of the loco weeds, 

 by Dr. C. L. Alsberg and Mr. O. F. Black, Chemical Biologists, has 

 been carried out with results which support the conclusion that 

 barium is not responsible for the trouble caused by these plants. A 

 publication covering these investigations is in an advanced state of 

 preparation. 



