- 5 - 



phylos. Aseleplas t Bapblsia, Campanula, Chrysothanmus. Comptonia , Cotinus, 

 Daucus, Eupatorlum, Euphorbia. Grindelia, Solldago, and Tragopogon yielded 

 acetone extracts between 20 and 30%» 



Table 2 gives a comparison of the acetone and benzene extracts from the 

 short and long extraction procedures. There Is little difference between 

 the benzene extract from these two extraction periods with species of Apocy- 

 num. Ascleplas, Campanula. Chrysothamnus. Euonymus . Lonlcera . and Solldago 

 but plants of the genus Lactuca yielded a much higher benzene extract (1.9- 

 2.9^) from the 20-hour extraction period than frcan the 3-hour period (0.6- 

 0,d%), Lactuca rubber apparently dissolves slowly Into benzene. In the 

 acetone extraction procedure the majority of plants yielded a slightly higher 

 extract from the 20-hour period than from the 6-hour period of the preliminary 

 analysis. 



ACKNOWLEDGMENTS 

 It is a pleasure to acknowledge the assistance of the many people par- 

 ticipating In this project. The collection campaign was organized by Dr. H. 

 A. Senn and the success of the program is evident from the many collections 

 received from all parts of Canada. Sincere thanks are extended to the numerous 

 collaborators who collected and forwarded plant material. Technical assis- 

 tance was given by A. Coghlan, L. Hogan, E.M. Lewis, K. Lochheed, D. Mcintosh, 

 H. Mitchell, and Dr. A. Skolko. Grinding and extraction of the plant material 

 was carried out in the Chemistry Division, Canada Department of Agriculture. 



SUMMARY 

 Some 1800 samples representing over 300 species of the native and intro- 

 duced plants collected at numerous stations throughout Canada were analyzed 

 by the extraction method for resin and rubber content. No hitherto unknown 



