HYDROCARBON CAROTENOIDS OP THE C40 SERIES 



535 



proportion of a-carotene found in the leaves of 59 species covering 40 dif- 

 ferent genera occurs in the white incense cedar {Libocedrus decurrens 

 Torrey) in which it amounts to 35%^' (Table 1). Large proportions of a- 

 carotene were also noted in magnolia leaves {Magnolia grandiflora L.) and 

 in the leaves of the English ivy {Hedera helix L.) in which the proportions 

 recorded were 20 and 15%, respectively. Strain^^ reported that leaves of 

 many common plants contain /3-carotene but no a-carotene; however, a 

 considerable number of leaves were shown to include small amounts of a- 

 carotene in addition to the /3-carotene. Considerable quantities of a-caro- 

 tene have been isolated from carrots, **'''^>**'^**^ from palm oil,*^ from the 



Table 3 



Sol KCES KROM WnU'H a-C-AROTENE Has BeEN ISOLATED" 



( footnotes to Table S on page S36) 

 >" P. Karrer, K. Schopp, and R. Morf, Helv. Chim. Acta, 15, 1158-1165 (1932). 



